CANBERRA: A government minister in Australia's most populous state placed herself in quarantine yesterday over concerns she was infected with H1N1 flu on a flight from Los Angeles, as the nation's confirmed cases of the virus more than doubled overnight.

The surge in Australia came as Singapore yesterday confirmed its first H1N1 flu infection, a 22-year-old woman who reported symptoms after visiting New York. In the Philippines, tests confirmed four more cases of H1N1 flu - including a 1-year-old girl who returned from the US and a 13-year-old boy who visited Hong Kong - raising the country's total to six.

In Australia, Tourism Minister Jodi McKay flew home to Sydney on Sunday on a Qantas flight from Los Angeles on which six passengers had by yesterday tested positive for H1N1 flu.