University of NSW epidemiology expert Mary-Louise McLaws told the Sydney Morning Herald that mandatory masks needed to be brought in before it was too late.
"How many people have to get Covid before they realise that it's a simple act of precaution?" Professor McLaws said.
It comes as health warnings were issued for multiple trains and bus routes this week, with a trainee bus driver working for days while infected with Covid-19.
Victoria recorded 113 Covid-19 cases and 23 deaths on Thursday, while NSW recorded nine new cases.