Clinical trials of a locally made nasal spray treatment for COVID-19 are set to begin in Victoria.

The heparin spray, made at Monash University's Medicines Manufacturing Innovation Centre, is expected to reduce viral load and potentially the spread of the virus within the body.

Heparin is the second most widely used drug in the world and is primarily prescribed to treat or prevent blood clots.

If the spray is proven effective, it could be used in high-risk COVID-19 settings like medical wards.

The six-month clinical trial will start later this year, with patient recruitment to begin through Northern Health in coming months.

Meanwhile, the Victorian government is reviewing mask mandates on public transport after NSW and South Australia became the latest states to scrap the rules.

Premier Daniel Andrews told reporters on Tuesday no decision on changing the mask requirement in Victoria had been made, but he was aware of recent changes in other states.

"The national cabinet only a short while ago made changes to the mandatory (isolation) periods," he said.

"We're all looking at these rules, but I don't have any announcements to make today about masks - but rest assured we're looking into those matters and all COVID rules."

Victoria, Queensland and the Australian Capital Territory are the only jurisdictions still requiring face masks to be worn on public transport.

The premier's comments come after more than 100 fines were issued on Victorian public transport since the start of September for non-compliance.

Additionally, authorised officers have spoken to more than 181,268 passengers in the same period as part of a crackdown to stop the spread of COVID-19.

Under Victoria's pandemic orders, passengers on public transport are required to wear a fitted face mask covering their nose and mouth while travelling on all forms of public transport unless they have a valid exemption.

The fine for failing or refusing to wear a fitted mask on public transport is $100 for an adult.

National cabinet agreed to scrap mask mandates for domestic flights from September 9 amid falling COVID-19 case numbers.

The Victorian government also lifted its work from home recommendation at the end of winter.