The worst-case scenario is based on no medical intervention, including antiviral treatment for people contracting the virus and vaccines.

"We could expect around 6000 deaths across the country," Ms Roxon said.

"That's really the worst-case scenario."

Ms Roxon said higher death estimates, drawn from a 2005 interim influenza pandemic action plan, were not applicable for the influenza A(H1N1) virus.

The plan estimated there would be 12,500 deaths from a pandemic with a 30 per cent infection rate.

That estimate was based on a "more severe flu", Ms Roxon said, adding that swine flu could be a severe disease for some people.

Swine flu has emerged as the dominant flu in Australia this winter with 10,387 confirmed cases.

The death toll has reached 23 with another death in the Northern Territory and a further 58 people with the virus are in intensive care units in hospital.

Ms Roxon said hospitals had plans in place to cope with the numbers.

"(But) it may well mean that some elective surgery or other procedures do have to be delayed."

Australia has ordered 21 million doses of vaccine against swine flu, which is due to be ready in October following clinical trials starting next week.