Dozens of domestic flights have been cancelled due to COVID-19, as Victoria records 2095 new cases and eight deaths.

The flights, axed on Christmas Eve, will mean last-minute disappointment for thousands of travellers.

About a dozen flights out of Melbourne Airport have been cancelled so far, with more Jetstar and Qantas trips disrupted out of Sydney, however many flights are taking off as scheduled.

The disruption has been caused by restrictions which have meant some airline staff must get tested and isolate.

It comes as Victoria records another eight deaths and an increase in active infections to 15,471.

Some of the latest cases have spread from Christmas carol rehearsals and performances at Melbourne's St Paul's Cathedral.

Members of the Royal Melbourne Philharmonic Choir, the Melbourne University Choral Society, Box Hill Chorale, the RMP Brass Consort and the Melbourne Highland Pipe Band were all involved in the events.

The health department says seven new cases are linked to the choir and orchestra performing Carols in the Cathedral, a series of four concerts held last week.

It has issued a reminder that singing can increase transmission of the virus, and says anyone thinking of attending group singing over Christmas should monitor for symptoms.

Meanwhile, Victoria's seven-day hospitalisation average is steady at 392, with a total of 397 patients in hospital, including 75 in intensive care, with 40 on ventilation.

A mask mandate for people eight years and older entering hospitality and entertainment venues and offices came into effect on Friday.

Masks will also be required at all major events with more than 30,000 patrons, including the Boxing Day Test at the MCG, but can be removed while seated outdoors.

They do not need to be worn in households.

Masks are already required in retail settings, for hospitality workers and on public transport.

The government is also recommending Victorians work from home over the festive season and hospitality venues are being asked to consider providing a seated-only service.

A lockdown is not being considered because of Victoria's high vaccination rate.