Test results for 10 New Zealand students believed to have contracted the potentially deadly swine flu will be known in the next 48 hours, Australian Chief medical officer Jim Bishop said on Monday.

"Australia has been assisting the people who are being looked at in New Zealand and the WHO (The World Health Organization) center in Melbourne is testing those individuals," Bishop told ABC Radio.

Dr Ian Barr, from the WHO Influenza Center in Melbourne, said it was unlikely any existing vaccines would be effective against the new swine flu strain.

"Authorities will be looking at that and testing people here ...who have been vaccinated with the current H1N strain. But it is likely that there will be no or very little cross-reaction, I suspect," Barr said.

On Sunday, the New Zealand government has announced 10 local students recently returned from Mexico were tested positive for influenza A and are believed "likely" to have contracted swine flu.

Three teachers and 22 senior students exhibiting flu-like symptoms have been kept in isolation when they returned from Mexico on Saturday after a three-week language trip.

Samples from the students have been sent to a WHO laboratory in Melbourne.

WHO has warned last week that the new influenza strain, feared to have killed 86 people in Mexico and infected 20 in the United States, has pandemic potential.