Children are hardest hit victims of A/H1N1 flu in Australia, with at least 21 children being found among the 44 confirmed cases of A/H1N1 flu, and 18 child cases in Victoria state alone.

Ten new cases of the A/H1N1 virus were identified in Victoria on Tuesday, with a further four cases in New South Wales and five in Queensland.

The NSW and Queensland cases were all passengers on the ship Pacific Dawn, which berthed in Sydney on Monday.

The number of A/H1N1 flu cases in Australia is expected to keep rising as Victorian authorities hunt for 36 cruise ship passengers they fear may also have contracted the virus.

A spokesman for Victorian health minister Daniel Andrews said all the latest victims came from Melbourne's north and west. Three Victorian schools have been closed because of the outbreak.

"We've imported the virus from overseas and it has started to spread unfortunately amongst Victorians, but I can't give a reason other than I think it's bad luck," acting Chief Health Officer Rosemary Lester was quoted by Australian Associated Press as saying in Melbourne, the capital of Victoria.

Almost 2,000 passengers disembarked from the Pacific Dawn on Monday, with 172 indicating they either had flu-like symptoms or had been in contact with someone with symptoms.