Victoria will tighten rules around medical exemptions to the COVID-19 vaccination, after people were caught doctor shopping.
Thursday is the state's deadliest day of the pandemic's third wave, after 25 Victorians died with COVID-19 and another 1923 new local infections were reported.
More than 77 per cent of Victorians aged 16 and over are now fully vaccinated after 22,189 doses were administered at state-run hubs on Wednesday.
Acting Chief Health Officer Ben Cowie said medical exemption requirements will change after GPs had complained of receiving "significant pressure" from people who do not want to get vaccinated.
He said GPs had reported "people travelling from clinic to clinic" seeking a medical exemption and doctors were calling for more clarity on the issue.
"A very small number of people are unable to get a COVID-19 vaccination because they have a condition," he told reporters.
"Victorian GPs are tasked with determining these exemptions when visited by their patients, but we have heard feedback from some of our GP colleagues that there have been some problems with this process."
From 6pm on Friday, patients asking for an exemption to avoid the jab will be required to present official proof of their exemption via an Australian Immunisation Register form.
People with a current exemption letter, that is not an AIR form, will need to return to their doctor so a form can be submitted on their behalf before November 12.
It comes as authorities warn there is high risk of thunderstorm asthma in the state's southwest, Wimmera and Mallee districts on Thursday, while Melbourne may be moderately affected.
The combination of high grass pollen levels, severe thunderstorms and strong winds on Thursday meant a "large number of people" may develop asthma symptoms quickly, the health department said.
Prof Cowie urged Victorians with asthma to be careful and follow their health plans, as he said there was already pressure on the health system due to COVID-19.
Australian Associated Press
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