There were 5919 new infections announced on New Year's Eve, another daily record, and seven deaths.

Positive cases have interrupted plans for many, including the audience of a matinee performance of Moulin Rouge who were told with 30 minutes to go and without explanation that the remainder of the show had to be cancelled.

In a statement organisers told AAP the show had been discontinued out of an abundance of caution, after a positive COVID-19 test result in the wider company. Future performances are also up in the air.

Performances of Frozen The Musical have also been cancelled until at least January 5 after COVID-19 cases were detected among the company.

Victoria moved on Friday to new isolation and close contact rules in line with definitions agreed at national cabinet on Thursday.

Positive cases in Victoria must inform their household and social contacts of their illness and can now isolate for seven days, rather than 10, regardless of vaccination status, Heath Minister Martin Foley announced.

Household contacts of positive cases must also isolate for seven days and can use a rapid antigen test if they are not symptomatic, but must get a PCR test if they show symptoms.

Workplace and school contacts are no longer required to get a test and isolate until they receive a result.

International travellers now have the option of completing a rapid antigen test on arrival - as well as on day five to seven - but are no longer required to isolate.

Case numbers are expected to continue growing as the more-infectious Omicron variant spreads, but Victoria is not anticipating another lockdown..

"These measures strike a balance between containing the risks of COVID-19 to help support a testing system that is efficient and effective in an environment of high case numbers," Mr Foley said.

"I'm confident that with the support of the community ... we can stay safe and we can stay safe open."

More than 66,700 tests were processed on Thursday, with sites buckling under the demand and having to close early in the day after reaching capacity.

Mr Foley said only people who have shown symptomatic signs of COVID-19 or tested positive in a rapid antigen test should get PCR tested.

With temperatures soaring across the New Year weekend, people are warned the weather will close testing sites too, where temperatures inside the tents can be 10C higher than outside.

Eighteen sites closed on Friday afternoon because of the heat.

While testing and isolation requirements are changing, Mr Foley said QR codes would continue to play a role in Victoria's fight against COVID-19 as they are a "key tool for early detection".

There are currently 28,044 Victorians with the virus, of which 428 are in hospital including 97 in intensive care.

However, there are fewer people on ventilators - 21 on Friday, down from 23 on Thursday and 28 on Wednesday.

Ninety-three per cent of the Victorian population aged 12 years or above has now been fully vaccinated.

More than 10 per cent of Victorians aged 18 or above have received their third dose.

Australian Associated Press