Victoria will give key workers another four weeks to get their third dose of a COVID-19 vaccine, after the state's chief health officer extended the deadline.

The state recorded 16 COVID-19 deaths on Thursday, along with 9391 new cases, including 6045 from rapid antigen tests and 3346 from PCR tests.

Victoria is managing 55,946 total active cases, while there are 543 patients in hospital with the virus. Of these, 75 are in intensive care and 23 on ventilation.

In the daily update on Thursday afternoon, Chief Health Officer Brett Sutton announced the key worker booster deadline will be extended by one month.

This means health and aged care, emergency, disability, quarantine and food distribution workers who were eligible for a third dose before January 12 will now have until March 12 to receive their booster.

Workers in those sectors who became eligible after January 12 must have received their third dose vaccine by March 29.

All healthcare workers eligible for a booster shot before March 12 must provide evidence of their vaccination status or a medical exemption to continue working, the CHO update said.

Employers must also confirm that an employee has received their third dose and keep a record of workers' third dose vaccination status.

About 48 per cent of Victorians over 18 have received a vaccine booster after 14,863 doses were administered at state-run hubs on Wednesday.