The WA Department of Health updated the state's coronavirus tally to include a new local coronavirus case, bringing the total number of local infections linked to the Perth Mercure Hotel to three.
The positive test result was received on Saturday afternoon, updating information given hours earlier by Premier Mark McGowan that there were no new local cases.
The state's health department said the new case is a male in his forties who presented for testing on Friday.
"The person is now working closely with the Department’s contact tracing team to determine ."
It is believed the new local case caught the virus at a restaurant, the Kitchen Inn in Kardinya.
Health officials are urging people if they did visit five restaurant locations between 17 April and 20 April.
The sites include: the Kitchen Inn, Anything La Corner in East Victoria Park; City China Garden in Northbridge, the Good Fortune Roast Duck House in Northbridge and Fortune Five Chinese Restaurant in Northbridge.
Mr McGowan said test results are forthcoming after contact tracers uncovered 337 contacts linked to the initial local case.
A 54-year-old Victorian man had completed his 14-day stay in hotel quarantine at Perth Mercure Hotel, but later tested positive for COVID-19.
The case triggered a three-day lockdown in the Perth and Peel regions, which is scheduled to end at midnight on Monday.
The Anzac Day dawn services in the lockdown areas were cancelled and people must wear masks when leaving their homes.
The governing body of RSL branches in the state, the RSLWA, said it is disappointing that an outbreak has disrupted official services, but there were still plans in place to mark Anzac Day.
"We will be pushing very hard the Light Up The Dawn driveway services, which happened last year and was very successful because no-one could go anywhere - and unfortunately that is exactly what has happened this Anzac Day," the CEO of RSLWA, John McCourt, told SBS News.
"They can converge in their driveway or balcony, or at the end of their farmgate; nod to their neighbours, light up a candle and commemorate."
Mr McGowan said he hoped the lockdown would not need to be extended.
"This has been a rapidly evolving situation. I know it has been difficult and I know it has been frustrating.
"But if we can all work together and do the right thing over the next few days, we'll increase our chances of stopping the virus in its tracks."
A woman who failed to wear a mask at the Super Rugby game at at HBF Stadium on Friday is the first person to be fined under the lockdown measures.
"I would characterise it as having failed the attitude test, so she has been issued with a $1,000 infringement," said WA Commissioner of Police Chris Dawson.
He urged people to abide by the rules.
"So please do not try and test this.
"The purpose of this is to support the Department of Health to protect us all and to stop people's movement over the next three days."
Call for national approach on hotel quarantine
WA Premier Mark McGowan said he remained deeply frustrated the federal government had not yet supplanted the hotel quarantine framework - established at the pandemic's outset - with permanent facilities.
He reiterated quarantine was a federal responsibility under the constitution but the states and territories were paying for hotel quarantine.
Mr McGowan suggested Commonwealth facilities at Curtin Air Base near Derby could hold 1500 people and Christmas Island could also be used, but hotels were not built to serve as quarantine hubs.
"CBD hotels are not fit-for-purpose quarantine facilities," he told reporters.
"It's time for the Commonwealth to step up and help - my government stands ready to work with them and help establish Commonwealth quarantine facilities, they have a range of facilities available.
"We cannot continue down this path for another year or beyond."
Mr McGowan also said he had written to Prime Minister Scott Morrison, requesting the immediate and potentially permanent halving - from 1025 people per month to 512 - of his state's hotel quarantine burden.
He said WA takes more returning travellers per capita than any other state and later accused Canberra of "not wanting" to do more on quarantine.
"They have divested responsibility and handed it to the states," hesaid.
"I'm getting to the end of my tether."
Documents released by the government this week identified the Mercure as one of three hotels considered "high risk" for ventilation issues.
WA's chief health officer received the report on April 8 and wrote to the premier last Friday advising that the Mercure should stop being used.
The Mercure will soon no longer accommodate returned travellers and the government will review the continued use of the other high-risk hotels.
Tests show spread of virus in hotel quarantine
Genomic testing has confirmed the virus initially spread in the corridors of the Mercure Hotel from a couple who had returned from India.
A pregnant mother and her four-year-old daughter who were staying across the corridor tested positive and remain in quarantine at the hotel.
A 54-year-old man, who tested positive upon arrival in Victoria, had been staying in an adjacent room.
He spent his first night out of quarantine at the home of a friend, a Kardinya mother-of-two who has also tested positive.
Her children have returned negative tests.
The man visited locations throughout the city, including popular tourist spot Kings Park, before leaving Perth on April 21.
Victoria reported no new locally acquired cases on Saturday.
States impose restrictions on travellers from WA
Victorian authorities are contact-tracing passengers and NSW Health has commenced screening of recent flights from Perth.
Meanwhile, Queensland will require anyone who has been in Perth or Peel since April 17 to comply with the requirements of the WA lockdown.
Just after midnight, South Australia shut its border to people from Perth or Peel aside from permitted and essential travellers.
Returning SA residents must now self-isolate for 14 days and arrivals from those areas since April 17 have been ordered to do the same until they receive a negative test result.
The WA government is encouraging those who attended exposure sites in the Perth and Peel regions to get tested. Source: SBS News
Tasmania has declared Perth and Peel high-risk regions, with travel and quarantine rules imposed for those coming into the state who may have been in those regions.
The NT has also declared Perth and the Peel region COVID-19 hotspots.
