A Victorian child under 10 has become Australia's youngest person to die with COVID-19, as thousands of protesters brought parts of central Melbourne to a standstill.

The state reported 1166 new locally acquired infections on Saturday as active cases dived to 9581, down by about 30 per cent from Friday.

Victoria's health department later confirmed the infected child was among five further deaths and had "other serious comorbidities".

Previously, 15-year-old Osama Suduh from southwest Sydney was the youngest known person in Australia to die with the virus.

The teenager died in August after contracting pneumococcal meningitis, and while he was also COVID-positive it was not the reason for his hospitalisation or death.

The latest deaths were announced as several thousand people gathered in Melbourne's CBD on Saturday to rally against Victoria's contentious pandemic bill - which stalled in the upper house this week - and COVID-19 vaccine mandates.

Watched on by police outside parliament house, protesters chanted "kill the bill" while carrying placards featuring a range of anti-government and anti-vaccine mandate slogans.

Independent MP Catherine Cumming, who said she would vote in favour of the pandemic bill if the government scrapped vaccine mandates, led a "no more mandates" and "sack (Premier) Dan Andrews" chant.

"We are adults. We make our own decisions for our children. Get out of our lives Daniel," she said during a speech.

The crowd grew as it marched to Flagstaff Gardens, where a band played John Farnham's You're the Voice amid a party atmosphere.

At least one protester was detained before being led away by police.

A counter demonstration at the nearby Eight Hour Day Monument attracted a smaller crowd in the hundreds and walked through other parts of the city.

A scuffle broke out near Lygon Street between a well-known right-wing activist and the anti-fascist protesters before police intervened.

Organiser Nahui Jimenez said the Campaign Against Racism and Fascism rallies in Melbourne, Sydney, Brisbane and Perth were designed to draw public attention to the "growth of conspiratorial, anti-human and fascistic politics".

"Hostility to vaccines has become a gateway to the far right globally," she said.

It has been reported figures associated with the neo-Nazi movement have recently joined the protesters, who on Monday evening staged a mock execution of the premier using wooden gallows.

Key Victorian crossbench MP Andy Meddick's daughter Kielan was also allegedly attacked on a Fitzroy street on Thursday night after being confronted by an unknown man for spray painting an anti-vax poster.

Meanwhile, Victoria will join NSW in allowing fully vaccinated international students to fly into the state without quarantining.

The state government has clarified international students can skip quarantine if they are double-dosed and provide a negative test 48 hours before departure, as per the requirements for all international travellers.

The first planeload of international students is expected to touch down in Melbourne next month under a plan ticked off by the federal government.

SNAPSHOT OF VICTORIA'S CORONAVIRUS OUTBREAK:

* Active COVID-19 cases: 9581, -4232

* New COVID infections reported on Saturday: 1166

* Deaths reported on Saturday: five

* Death toll across the pandemic: 1273

* COVID-related patients in hospital: 312, -18

* Seven-day hospitalisation average: 357, -14

* Actively infected patients in ICU: 55

* Cleared patients in ICU: 59

* ICU patients on a ventilator: 24

* Tests administered on Friday: 64,050

* Vaccine doses administered at state-run hubs: 6920

* Vaccination rate in over-12s: 89 per cent.