LATEST COVID-19 DEVELOPMENTS:
* Victoria's Acting Premier James Merlino announced the most significant easing of restrictions since the start of the COVID-19 pandemic.

* From 6pm on Friday, Victorians will be able to have 100 visitors at home, up from the previous cap of 30, while public gatherings can double from 100 to 200.

* Masks will no longer be required in retail settings, though Victorians will still need to wear them on public transport, in taxis and rideshare vehicles and in aged care facilities and hospitals.

* Density limits will be eased at casinos, nightclubs and karaoke venues from one person per four square metres to one person per two square metres, bringing the venues into line with cafes, pubs and restaurants.

* Crowd numbers have also been increased to 75 per cent of stadium capacity in time for round two of the AFL, meaning about 75,000 fans will be able to watch Carlton play Collingwood at the MCG on Thursday.

* Victoria cleared its last active case on Tuesday, a year to the day after the state entered its first of three lockdowns.

* Victorian Chief Health Officer Brett Sutton warned the risk of coronavirus outbreaks could increase as the weather cools and people spend more time indoors.

* Mr Merlino said government-commissioned reviews into variant strains of COVID-19 and ventilation at the state's quarantine hotels were complete, paving the way for international flights into Melbourne to soon resume.

* The Morrison government has faced questions about the adequacy of its COVID-19 support to Papua New Guinea as Australia's vaccine rollout gains pace.

* An AUSMAT team was dispatched to PNG on Tuesday with 8500 vaccine doses and medical supplies.

* Labor frontbencher Bill Shorten, who has spoken with contacts in PNG, said there was a humanitarian disaster unfolding as 400 new cases were recorded there overnight.

* Health Minister Greg Hunt told parliament the government would step up support for its northern neighbour.

* There have been 312,000 COVID-19 vaccinations given nationally, up 10 per cent in the past 24 hours.

* Mr Hunt noted AstraZeneca vaccine clinical trial data released overnight had shown 100 per cent effectiveness against serious illness, hospitalisation or death.

* NSW and Queensland were the only states to report overseas acquired cases on Tuesday.

AUSTRALIAN CORONAVIRUS NUMBERS:
* Australia reported no new locally acquired case of the coronavirus on Tuesday. Seven overseas acquired cases were reported in hotel quarantine: four in NSW and three in Queensland.

* The national death toll is 909: Victoria 820, NSW 56, Tasmania 13, WA 9, Queensland 6, SA 4, ACT 3 (Two Queensland residents who died in NSW have been included in the official tolls of both states).

GLOBAL CORONAVIRUS NUMBERS:
* Cases: at least 123,676,000

* Deaths: at least 2,722,000

* Recovered: at least 70,137,000.

Data current as of 1700 AEDT on March 23, taking in federal and state/territory government updates and Johns Hopkins Coronavirus Resource Centre figures.