South Australia has imposed a range of new local COVID-19 restrictions in response to the growing number of virus cases around the country.
As of midnight Monday, masks are mandatory in high-risk settings including aged care facilities and hospitals and are highly recommended on public transport.
A new density arrangement of one person to every two square metres is being enforced in cafes, pubs, restaurants and other venues while private gatherings are limited to 150 people.
People consuming food and drink at indoor venues must be seated.
Premier Steven Marshall said it was hoped the new measures would only be required for a week.
But he said the government had to act quickly given the potential for the rapid spread of the Delta variant of COVID-19.
"Given the nature of the rapid spread of the Delta variant we have no option but to take pre-emptive action to keep South Australians safe," the premier said.
"We have to be very vigilant at the moment."
The new measures follow SA's move on Sunday to close its border to Queensland, WA, the NT and the ACT after previously locking out travellers from NSW.
Chief Public Health Officer Nicola Spurrier said all the new restrictions and rules tried to balance the risk to health with the economic and social impact.
She said there were no new virus cases reported in SA on Monday, with all 29 miners from the Northern Territory, who were potentially exposed to the virus, returning negative results.
The workers were among 900 fly-in-fly-out personnel who recently left the Granites mine, north of Alice Springs, where one person tested positive last week.
Six virus cases have now been linked to the mine, including three in Darwin.
SA Health said the miners remained in isolation, along with their families.
