"It is very likely that we will have some hundreds of deaths in the next few months. That's not good and we need to minimise that," Professor Collignon, of the Australian National University, said.

"People are going to die. We're going to have quite a few infections in Australia. But when we say we're expecting 10,000 to 20,000 deaths by the end of May, we might have to plan for that, but I personally think that's not very likely to happen."

Even in the Hubei, the home of the outbreak, less than 1 per cent of the population had been infected, with about 3100 recorded deaths. Professor Collingon said even if China was assumed to have missed virus deaths as the outbreak overwhelmed the health system, a doubling or tripling of the China infection and death rate still didn't come near the scenarios being discussed in Australia.

"On the data we've got available at the moment even in Hubei, it wasn't 20 to 60 per cent [infected] so I'm not sure why we're assuming that should happen in Australia."

Professor Collignon was referring to modelling cited by Australian authorities which suggests 20 per cent of the population could become infected in the first wave, which is 5.1 million Australians and about 84,000 Canberrans (on a population of 420,000).

Of them, the modelling suggests 5 per cent could need intensive care - which is 255,000 people around the country and 4200 in Canberra. And 1 per cent could die - 51,000 deaths nationally and 840 in Canberra.

The figures were cited by NSW Chief Health Officer Kerry Chant in estimates hearings in that state. German Chancellor Angela Merkel has said up to 60 per cent of Germans could get infected, which in Australian terms would be a whopping 15 million infections and 150,000 deaths.

Dr Chant's figures are understood to be the ones being used nationally, but the federal government has refused to confirm this, leaving people to speculate.

On Monday, when Deputy Chief Medical Officer Paul Kelly was asked about the 20 per cent and 60 per cent infection estimates, he said authorities were working on a figure in that range, and on a death rate of about 1 per cent of infections.

But Professor Collignon said those numbers did not reflect what had happened anywhere so far, with an infection rate of probably about 1 per cent in Wuhan and 0.1 per cent in China. Australia had the advantage that it wasn't yet winter, smoking rates were lower, and services such as public water supplies were better.

"Why do we think that's going to happen in Australia?" he asked. "I don't want to downplay this. This is serious, we are going to have deaths in Australia and increasing deaths, but [the modelled infection rates] are not what appears to have happened so far in places that have had this pandemic go through - China, Japan, Singapore, Korea, Hong Kong.

"We should be able to do at least as well as China in stopping the spread."

Professor Collignon called for more targeted advice aimed at people over 50 and especially over 70, where death rates were significantly higher, perhaps 10 per cent in over-80s.

READ MORE:

The elderly had perhaps 100 times the death rate of people in their 20s and 30s. The death rate for anyone infected under 40 was only 0.1 per cent, or one in 1000.

"The ones we've got to look after are those aged over 50 but definitely over the age of 70, where we should really concentrate on self isolation and relative social distancing," he said.

People in those groups should stay home more, and while they should still get outside and walk round the neighbourhood, anyone with a cold or cough should stay away and other visitors should stay at a safe distance. Anyone unwell in the household should wear a mask, and care should be taken to clean surfaces and wash hands, he said.

"I've got parents in law in their 90s. I think this is a real risk that we're going to see a lot more people die than would have otherwise died," he said. "But the thing is to keep this in perspective, because if we paralyse society completely with fear there's going to be collateral damage, people not getting service for other conditions."

Nor did Professor Collignon back calls for much more widespread testing, saying testing was already substantial - with fewer than 1 per cent of tests now proving positive, and no point in tests without symptoms. The priority must be to test medical and nursing staff so they didn't spread illness to hospital staff and patients, and people who needed hospitalisation so they could be isolated and treated if they were positive.

We have removed our paywall from our stories about the coronavirus. This is a rapidly changing situation and we want to make sure our readers are as informed as possible. If you would like to support our journalists you can subscribe here.