The number of confirmed swine flu cases in New Zealand has risen by two.

Laboratory tests confirmed two cases, previously classed as probable, were swine flu, bringing New Zealand's total number of confirmed cases to nine, the Ministry of Health said today.

The two cases included an Auckland college student who had returned from Mexico and another passenger from the same flight.

The confirmation of the two brings the total number of probable cases down to 10. All the people with confirmed cases, including the two today, and probable cases had been treated and had fully recovered, the ministry said.

Forty others, one fewer than yesterday, were classed as having a suspected case of the flu.

There were still nine people in isolation and being treated with Tamiflu, the ministry said.

The number of people in isolation peaked above 400, and has been steadily dropping as people complete 72 hours of the five-day course of Tamiflu.

The swine flu alert was first sparked in New Zealand when the party of Auckland college students returned from Mexico via Los Angeles on April 25.

Worldwide, 33 countries have officially reported 5728 cases of swine flu, according to the World Health Organisation.

There have been 56 deaths in Mexico, three deaths in the United States, one death in Canada and one in Costa Rica.