"We are seeing hundreds and hundreds of thousands of Australians infected every single week in this wave. As of today, there are more than 5200 Australians in hospital with Covid. That number has increased very dramatically over recent weeks."
The chief medical officer Professor Paul Kelly said the new variant in the community was much more infectious than previous strains.
"It's also very good at escaping immunity, whether that is from previous infection so, you can get reinfected," he said.
"So whilst vaccination, as the minister has said, continues to offer very good protection against severe disease and death, and I would reiterate what the minister said absolutely to go and get that third dose if you're due or get the fourth dose if you are now eligible. Those vaccines do not stop the transmission of this virus, and this variant is unusual in that case."
Professor Kelly said he was trying to play a "leadership role" by wearing a mask.
"We know that wearing masks do reduce the spread and protect yourself and protect others if you're away from home and indoors in a crowded place, I really very strongly suggest that you do wear masks," he said.
"I am wearing a mask now. You will have noticed the minister is wearing a mask as well. This is our leadership role for the community. This will not be forever but for the next few weeks this is the way we can actually influence."
But Butler said it was not a mandate.
"That is not the advice that was issued by the Chief Health Officers last week," he said.
In a statement, the chief medical officer said all the indications and weekly forecasting reports suggest that cases will continue to rise in Australia over the coming month.
"Due to the number of cases, we may also see a rise in the number of people dying with Covid-19, particularly among those who are at higher risk of severe disease, most notably people over the age of 80 and those who have not received all recommended vaccine doses," he said.
"We cannot stop this wave of infections, but we can slow the spread and protect the vulnerable. We have done this before and we can do it again. In fact, a range of measures and advice provided in the past two weeks gives us a clear, scientifically-based path to achieve these dual aims.
"The Australian Health Protection Principal Committee (AHPPC) has reiterated its advice on reinfection periods, testing and isolation, mask wearing, vaccine boosters and treatments and called on employers to allow work from home if feasible.
"Employers should review their occupational health and safety risks and mitigations, and their business continuity plans. They should consider the feasibility of some employees working from home, wearing masks in the workplace and support employees to take leave when sick."
In some good news, almost 560,000 fourth doses were administered in the first week of the expanded rollout, compared with approximately 180,000 the week before – a threefold increase.
"I also encourage everyone to follow the recent advice of the AHPPC and wear masks when outside the home in crowded, indoor environments, including on public transport. This is important to protect yourself and others," he said.
"Physical distancing, where possible, and following good hygiene practices provide additional layers of protection. Undertake a test if you have any symptoms and stay at home if you have Covid-19.
"Check your eligibility for antiviral treatments with your usual health provider and make a Covid treatment plan so that you know exactly what to do to access that life saving treatment before you get sick."
