Victoria will soon widen access to rapid antigen tests to ease testing pressure after a heatwave forced the closure of some PCR sites.

The state reported 7172 new COVID-19 infections on Sunday and another three virus-related deaths.

Extreme heat caused the closure of eight of the state's testing sites on Saturday, blowing out queues and test result wait times.

Early Childhood Minister Ingrid Stitt said there had been "unprecedented demand" on the testing system in recent days.

Despite reports that some people were waiting up to four days for their COVID-19 test results, she said results were "overwhelmingly" still coming through within 24 to 48 hours.

"I think yesterday's heat, which affected some of our centres, may have something to do with some of the longer waits," she told reporters at parliament on Sunday.

"We are committed to making sure that we continue to deliver results as quickly as possible and I know that our hard-working pathology services are working really closely with us on that."

She said the state's health minister will make an announcement on widening access to rapid antigen tests within days.

"We will have more to say in the next few days about how we will distribute rapid antigen tests for those who are eligible to use that as a way of ensuring they remain COVID-safe," she said.

It comes after Victoria moved to new isolation and close contact rules in line with definitions agreed at national cabinet.

Positive cases must inform their household and social contacts of their illness and can now isolate for seven days, rather than 10, regardless of vaccination status.

Household contacts of positive cases must also isolate for seven days and can use a rapid antigen test for the all-clear 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.

The number of coronavirus patients in hospital care remains relatively stable at 472, up 19 on Saturday's figure and 48 beyond the seven-day average.

Of them, 52 are classified as active ICU cases and 22 are in need of ventilation.

In total, Victoria is managing 31,461 active COVID-19 cases.

Health authorities says virus testers managed to process 48,252 results in the 24 hours to Saturday evening.

About 93 per cent of Victorians aged over 12 have received two doses of a COVID-19 vaccine.