In a late night tweet, the government said from 11.59pm on Wednesday face mask rules would change for anyone aged 12 and above.

Face masks will be mandatory indoors, including all workplaces and secondary schools, (not at home) unless an exemption applies.

It comes as 11 new cases of COVID-19 emerged in Melbourne's north and west on Wednesday from two separate outbreaks, both of which stem from NSW.

A teacher from Bacchus Marsh primary school is among the new cases, having reportedly attended an AFL match between Carlton and Geelong at the MCG on Saturday with an infected friend who lives at the locked-down Ariele Apartments in Maribyrnong.

All the latest exposure sites are here.

And one expert wants the nation to understand just why the latest strain of COVID-19 is even more dangerous than you first thought. It's scary. Watch more here.

Meanwhile in Tokyo preparations for the Olympics continue and details of the DIY medal presentations have been revealed.

There will be no dignitaries, no handshakes, no hugs.

Instead, the three medals will be presented on a tray to the athletes on the podium and they then have to hang them around their own neck in front of the empty stands.

In other Olympic news, a coronavirus cluster at a Japanese hotel where dozens of Brazilian Olympic team members are staying has raised new concerns about infections.

Organisers say the 31-strong Brazilian Olympic delegation, which includes judo athletes, are in a "bubble" in the hotel and separated from other guests and have not been infected.