As COVID-19 cases rise again in parts of Australia, so does the number of contacts having to isolate.
Self-isolation rules and definitions of close contacts of a confirmed COVID-19 case are changing in some jurisdictions as authorities manage the new Omicron variant.
For example, New South Wales authorities this week announced a change to the definition of a close contact that will now mainly be focused on households.
The Australian Capital Territory has also relaxed quarantine requirements for close contacts of cases linked to Omicron.
Here are the current rules for each state and territory.
New South Wales
In NSW, many who have attended hospitality venues and nightclubs in Sydney and Newcastle were recently placed in isolation for one week after being classified as close contacts.
Health authorities are concerned about escalating case numbers in the Newcastle area linked to several superspreader events. Among them is an outbreak at the Argyle House nightclub on 8 December, with more than 200 out of 680 revellers since testing positive.
Anyone who was at the nightclub from 9pm on Wednesday 8 December to 3am on Thursday 9 December has been deemed a close contact and must immediately get tested and isolate for seven days.
Separately, anyone who attended Finnegan's Hotel from 6.30pm Friday 10 December to 2.30am on Saturday 11 December is a close contact and must follow the same rules, NSW Health said on Wednesday. 
In a change announced on Wednesday, NSW Premier Dominic Perrottet said the definition of close contacts will mainly be focused on households.
Healthcare workers administer COVID-19 tests at a drive-through testing clinic at Bondi Beach in Sydney. Source: AAP
"If you are deemed to be a close contact, it would generally be a member from your household," he said.
"There may be occasions where [NSW] Health may determine outside of that definition that you would be a close contact. In those circumstances, rather than having to isolate for seven days, you will just need to get a negative PCR [nose and throat] test."
A spokesperson for NSW Health said fully vaccinated contacts will only have to isolate until they receive a negative PCR test. However, household close contacts and close contacts in any other settings identified by NSW Health will still be required to isolate for seven days and comply with PCR testing requirements.
"The vast majority of people currently isolating were identified as close contacts because they are household contacts, or are linked to high-risk settings or high-risk exposure," they said.
"These people will be required to stay there until they have completed seven days of isolation and returned a negative PCR result on day one and day six.
"NSW Health will contact the small minority of people currently isolating who will now be advised they can leave isolation after returning a negative PCR result."
Chief Health Officer Dr Kerry Chant said the changes reflect a move to "light touch" contact tracing given the caseload.
NSW Premier Dominic Perrottet. Source: AAP
"We know the greatest risk that people will have will be household contacts," she said, adding there will be some cases in addition to household contacts identified as high-risk.
"And then there will be times, like where we have the nightclub in Newcastle, where it's pretty evident pretty quickly that that was a super-spreader event, so we immediately alerted people to make sure everyone was aware of that risk," she said.
Self-isolation means you must stay at your home or accommodation and remain separated from others, even if you are fully vaccinated or feel well.
Victoria
Meanwhile, more than 700 Victorians have been forced into isolation after attending Sircuit Bar in Fitzroy or the Peel Hotel in Collingwood on Friday night.
About 410 people at Sircuit and 320 at the Peel have been deemed as close contacts. They must get a PCR test immediately and isolate at home for seven days if fully vaccinated, or 14 if not.
Victoria's health department defines contacts under four categories: household (someone who lives with a diagnosed person or has spent more than four hours with them in a house, accommodation or care facility), social (someone who has spent time with a case but doesn't live with them), workplace (a worker who was in the same indoor space as an infected worker) or education (someone who was in the same indoor space with a diagnosed person, or whose child was).
Those who are deemed household contacts must quarantine at home for seven days if fully vaccinated and 14 days if not. They must get a PCR test as soon as possible, and monitor for symptoms while in quarantine.
Those who are fully vaccinated are required to get tested again on day six before leaving quarantine on day seven after a negative result is received. Those who are not fully vaccinated must get tested on day 13 and can leave on day 14 upon receiving a negative result.
Social contacts are strongly recommended to get a PCR test and isolate until receiving a negative result. Workplace or education contacts must immediately isolate from the time of being notified, get a PCR test within 24 hours and isolate until a negative result is recorded.
The department says it might directly provide advice to other contacts who have attended a high-risk public venue visited by positive cases.
Queensland
In Queensland, most passengers who were on a flight with a positive COVID-19 case who had recently been in Newcastle will be reclassified from close to casual contacts and no longer required to quarantine for 14 days.
People considered close contacts in Queensland must immediately quarantine for 14 days from the time they were at the venue, and get tested at their earliest opportunity. They must also complete , after which they will be contacted by Queensland Health.
They are required to continue to quarantine even after receiving a negative result.
Those who live with a close contact are considered secondary contacts and must immediately quarantine for 14 days or until receiving further instruction from authorities.
They're only required to get tested if symptoms develop, after which they must isolate until a negative result is received, or if anyone in their household tests positive.
Casual contacts are required to quarantine and get tested at their earliest opportunity until receiving a negative result, while low-risk contacts must get tested but are not required to quarantine.
Australian Capital Territory
Close contacts in the ACT are required to immediately quarantine, complete an ACT Contact Declaration Form (unless directed otherwise when contacted by ACT Health), get tested immediately and follow any further advice.
Quarantine and testing rules depend on vaccination status. The fully vaccinated must quarantine for seven days after their exposure and regardless of a negative test result. They can leave quarantine after seven days, but are required to test again on day six and day 12 or 13.
Those who are not fully vaccinated are required to quarantine for 14 days after their exposure, regardless of a negative test result. They'll also need to test on day six and 12 or 13, after which they can leave quarantine the following day once a negative result is received.
On Wednesday, authorities announced quarantine measures for close contacts linked to Omicron will be relaxed in the ACT, despite a rise in cases linked to the new variant.
Fully vaccinated close contacts of Omicron cases will now only need to quarantine for seven days as opposed to 14.
The changes will come into effect from 11.59pm on Wednesday.
However, ACT health authorities have urged close contacts of Omicron cases to limit their movement in the community during days eight to 14 since their exposure.
Household contacts of Omicron close contacts will no longer be required to quarantine as a secondary contact.
However, unvaccinated close contacts will still need to undergo 14 days of quarantine.
ACT Deputy Chief Health Officer Vanessa Johnston said those coming out of quarantine after seven days should limit their gatherings in the community and avoid venues with large numbers of people.
South Australia
Multiple exposure sites have been identified in South Australia as it reported 26 new COVID-19 cases, with about 1,400 people in quarantine.
The state introduced a new Test, Trace, Isolate and Quarantine (TTIQ) model on 23 November, which SA Health said will ensure fewer people are required to quarantine, and more can quarantine for shorter periods.
"Under the new TTIQ model, anyone identified as a casual contact or a close contact of someone who is COVID-19 positive will be advised by SA Health and provided with advice on what is required with regards to quarantining and getting tested," it says.
Western Australia
Western Australia's health department says it contacts all confirmed COVID-19 cases to identify and inform close contacts.
"When close and casual contacts in a location can be comprehensively traced such as a workplace, family’s house, or friend’s house there is no need to publicly release the location, as all contacts are tracked and contacted as a priority," it says.
"However, when the positive case has visited publicly accessible locations and close and casual contacts are not as readily identifiable, the location is released to assist with the public health response."
The department has published Those who visited the sites during the listed times are urged to get tested immediately and isolate until a negative result is received, unless directly advised otherwise by the department.
Northern Territory
In the Northern Territory, contacts are defined under four categories: close, casual or low-risk contacts, or locations of concern.
Those who have been to a public exposure site listed at the relevant dates and times must quarantine immediately, call the COVID-19 Hotline on 1800 490 484 and get tested. They'll need to quarantine for 14 days.
Casual contacts must immediately quarantine, call the hotline and get tested, but are only required to quarantine until a negative test is received. They're advised to monitor for symptoms for 14 days.
Low-risk contacts are required to monitor for symptoms for 14 days and quarantine and get tested if symptoms any develop. Those who attended a location of concern must get tested and quarantine until a negative result is received, and continue monitoring for 14 days.
Tasmania
In Tasmania, those who have been to an exposure site visited by someone with COVID-19 might be deemed a close, casual or low-risk contact.
A close contact is generally someone who has had at least 15 minutes face-to-face contact with a confirmed case, such as household, social or workplace contacts.
Close contacts who are fully vaccinated must quarantine immediately and get tested. They'll be required to get tested on day five or six and can leave quarantine after seven days if their results are negative. For the next seven days, they're asked to avoid high-risk settings and get tested against on day 12 or 13.
Those who are not vaccinated must quarantine immediately for 14 days from their exposure. They'll need a test at the start of their quarantine, and on day 12 to 13 and will be released after 14 days with negative results.
Casual contacts are defined as someone who has been in the same place as a confirmed case but does not meet the requirements for a close contact. They're not required to quarantine but are asked to wear a mask for 14 days from their exposure, and get tested between days three and five.
If casual contacts - vaccinated or unvaccinated - develop symptoms, they should isolate and get tested immediately.
With additional reporting by AAP.
