State public and environmental health services senior medical adviser Mark Veitch said yesterday that travellers to the northern hemisphere winter were at some risk of catching flu.

"Each year a small number return to Australia at around the time that they become ill," Mr Veitch said.

"Flu is more difficult to spread during the southern Australian summer and it is uncommon for returned travellers to cause more than an occasional further case."

Mr Veitch said that one of the most common strains in New York was Influenza A/H3N2, which was quite common in Tasmania last winter.

He said that the strain was included in the state's 2013 vaccination regime and that the vaccine would become available in Australia from about March.

"It has been different to the 2012 vaccine and has been updated to provide protection against the strains of influenza expected to circulate here during our winter," Mr Veitch said.

New York state became the latest US region to declare a health emergency at the weekend due to a flu epidemic.

The number of confirmed cases were reported as already four times higher than last year.

At least two children and 10 adults have died from influenza this season in New York city alone.

Reports from the US say that widespread flu has been reported in 47 states.