Sydney

People have been advised to avoid non-essential travel and many have been working from home.

Some schools have closed early, or chosen not to open at all, while the extreme heat is putting pressure on the health service.

But countries where temperatures are usually higher have adapted their infrastructure and lifestyle to cope with the heat.

There is no extreme temperature threshold that forces Australian schools to shut. For some students, this knowledge can really melt your icy pole [ice lolly].

The laboratory's medical director professor Anthony Dodds blamed the mistake on the "large volume of tests" they were processing.

Those affected were notified of their result, for swabs taken from December 22 and December 23, last night at 8pm.

Professor Dodds said they had become aware of the mistake this morning.

"These people had tested positive to Covid," he said.

"As soon we became aware of the issue this morning, SydPath immediately commenced a process to contact impacted people.

"We sincerely apologise to all those impacted."

People queued for pubs and bars that opened at midnight on Monday specifically for the occasion.

Many others have been enjoying anticipated reunions and visits to the homes of relatives and friends.

Covid rules had banned household visits and travel beyond a 5km (3.1 miles) zone, separating many families.

But most restrictions have now been eased for fully vaccinated people.

People can now share meal together at reopened cafes and restaurants, and visit gyms and other shops. There were long queues for barbers, nail salons and beauticians on Monday.

The Delta outbreak, which began in Sydney's eastern suburbs 54 days ago, has been concentrated around Fairfield, in the city's south-west, for several weeks.

But 92 of 319 new cases recorded in the 24 hours to 8:00pm Friday were from the Canterbury-Bankstown local government area (LGA), sparking warnings the virus was on the move again.

NSW Health Minister Brad Hazzard said there had been "a rapid increase" in COVID infections in the LGA this week, with around 500 new cases identified.

The New South Wales Premier, Gladys Berejiklian, says while the number are higher than yesterday, a positive is that officials haven't seen evidence of the virus spreading significantly outside the Northern Beaches.

Everyone in the Greater Sydney area, including the Blue Mountains and Central Coast, is now asked to have no more than 10 people in their homes until Wednesday.

The Northern Beaches region remains in lockdown.

Melbourne Storm were to host the Warriors at their home ground but will instead clash in Sydney, the NRL said following consultations with biosecurity experts.

"I want to thank the Melbourne Storm players for putting the game ahead of their personal circumstances," NRL acting CEO Andrew Abdo said in a statement.

Victoria state, of which Melbourne is the capital, has recorded double-digit rises in new Covid-19 infections, accounting for nearly 90% of the 126 cases detected nationally over the past week.

On Tuesday, level two restrictions were enacted in the capital of New South Wales (NSW), a state 99.9% in drought.

These could be increased to level three within months, local media report.

Temperatures are predicted to soar above 40C (104F) from Tuesday, worsening fires which have already killed six people since October.

There are now more than 100 fires in NSW and Queensland states, many of which have been burning for several weeks.

What are the water restrictions?

A second woman was found dead inside an apartment building on the same street.

"All the information we have at hand would link these two crimes," police commissioner Mick Fuller said at a press conference.

He said the suspect was a "lone actor" with a history of mental health issues.

He was known to police but "his history was unremarkable compared to the gravity of the crimes he committed", Mr Fuller said.

The police commissioner said the suspect had some ideologies related to terrorism, but had no apparent links to other terrorist organisations.

The event will be attended on PNG’s behalf by the Chief Justice, Sir Gibbs Salika, and Deputy Speaker of Parliament Jeffrey Komal, and Acting PNG High Commissioner to Australia, Sakias Tameo.

They will be accompanied by other Pacific Islands Nation dignitaries to attend the event which aims to promote peace around the world.

It is forecast to reach 33 degrees Celsius in Sydney city, and 40C in western suburbs.

On Sunday, a reading of 47.3C was recorded in Penrith by the late afternoon, making it the hottest temperature recorded in Sydney since 1939. It was also the hottest city on Earth.

The Australian and England cricket teams suffered temperatures in the 50s out on the field at the Sydney Cricket Ground.

England captain Joe Root was taken to hospital to be treated for severe dehydration.