All primary schools and nurseries in Hong Kong are to shut for 14 days from Friday in a bid to contain the virus, the territory's chief executive Donald Tsang said.UN health officials are expected to declare the first global flu pandemic in 40 years, after holding emergency talks on the swine flu crisis.
The World Health Organization called the meeting after a steep rise in the number of cases in Australia.
Hong Kong on Thursday announced it was closing all its nurseries and primary schools for two weeks after 12 students tested positive for the virus.
The last global flu pandemic came in 1968 over the Hong Kong flu.
That pandemic killed about one million people.
A disease is classed as a pandemic when transmission between humans becomes widespread in at least two regions of the world.
The latest virus emerged in Mexico in April and since then thousands of cases have been confirmed throughout North and South America.
The H1N1 strain has spread to 74 countries but the WHO has so far resisted labelling the outbreak a full-blown pandemic.
It follows confirmation that 12 secondary school pupils have contracted the illness. Secondary schools are not yet being ordered to close.
At least 50 people are now confirmed to have the virus in the territory.
Keiji Fukuda, head of the WHO influenza programme, has claimed the "Swine Flu virus has evolved significantly" in the past few days.
BBC NEWS | Asia-Pacific | WHO 'set to declare flu pandemic'