The Federal Government has warned against people attending swine flu parties to catch the virus and develop immunity before it can mutate into a more severe form.

Media reports say such parties have been held in the US, allowing healthy kids to have contact with sick ones in the hope they will get the virus and develop immunity before any second wave of the virus.

One parent in Melbourne told The Age of hearing people talking about the concept locally, but did not know anyone who had acted on it.

Federal Health Minister Nicola Roxon warned today that the idea of swine flu parties carried risks.

"I don't think having events aimed at spreading the disease is a good idea," she told reporters.

So far, the vast majority of swine flu cases globally have resulted in relatively mild illness.

However more than 100 people have died, mostly in Mexico, and experts have warned that it could mutate into a more severe form.

Ms Roxon said a healthy debate was under way about when authorities in Australia should allow swine flu to run its course.

She said there would be less concern about allowing that to happen once experts had more confidence it was always going to be a mild illness.

But she warned: "I just don't think we are at that point yet."

The national swine flu infection tally now stands at 878 confirmed cases, including 752 in hardest hit Victoria.

Most of Victoria's cases are clustered in Melbourne's north and west.

Australian swine flu cases represent about 2.6 per cent of the 19,273 cases reported in almost 70 countries. None of the 117 deaths so far have occurred in Australia.

Ms Roxon said the incidence of swine flu remained on an upward trajectory.

"I would have thought we are not at the halfway point, given that we still don't have an extensive spread in Australia," she said.

She said a vaccine was not yet available and all efforts were being directed at containing the disease.

"The reason it is a marathon is we will potentially have this disease with us not just through this flu season but a risk of it again in the following year," she said.

"We will of course by that time have a large proportion of the community vaccinated and the risks will be different."

CANBERRA AAP