Two children on board a cruise ship that returned to Australia on Monday have tested positive for swine flu, bringing to 22 the number of people in the country with the virus.
The boys were among four passengers from the Pacific Dawn tested for the virus, but the two others were diagnosed with general influenza.
The testing delayed the departure of the vessel on its next cruise by seven hours and 130 other passengers were quarantined with symptoms of respiratory illness.
New South Wales chief health officer Kerry Chant said the children were treated with Tamiflu and would be isolated for 24 hours until they were symptom-free.
The remaining 1,800 disembarking passengers were asked to stay at home or in their hotels for up to seven days.
The ship eventually set sail with its new passengers and a fresh crew on Monday night.
Three schools in Victoria and two in South Australia remain closed as authorities grapple with the swine flu outbreak. Victoria is the hardest hit state, with 13 cases.
School children returning from swine flu-affected countries in the Americas and Asia will be quarantined under new measures announced on Monday by Health Minister Nicola Roxon.
Victoria, South Australia, NSW, Western Australia, Queensland and the ACT have announced all school children returning from the United States, Canada, Mexico, Panama and Japan should be kept from school for seven days.
Cruise ship delays
On Saturday, authorities decided to quarantine the Dawn Princess's 2,000 passengers and 900 crew on the ship for more than five hours.
Four passengers were later cleared of infection. They tested negative for influenza A, with health authorities saying there was no need for additional testing for swine flu.
On Sunday, 33 airline passengers were referred to the Sydney Airport Influenza Clinic after 208 passengers were assessed.
NSW Health said three of the passengers met the "suspected case" definition and are awaiting test results.