Wellington  - Nearly 70 New Zealanders may have contracted swine flu following recent visits to Mexico or the United States, health officials announced Tuesday.

Another 56 people who had developed flu-like symptoms were being tested to see if they had the influenza A strain, which has been linked with the outbreak of swine flu, H1N1, that the World Health Organization said was evolving rapidly.

They are in addition to 10 teenage students from Auckland's Rangitoto College, who were confirmed positive for influenza A after returning from a study trip to Mexico and are awaiting the results of swine flu tests at a WHO laboratory in Australia.

A total of about 100 New Zealanders, who have been in contact with swine flu suspects, are in voluntary quarantine pending the WHO test results.

The Ministry of Health said that two students from another Auckland college and a parent who also returned from Mexico on another flight via Los Angeles on Saturday were found not to have influenza A.

As a result, the ministry is no longer trying to contact about 300 passengers who were on that flight with the party of 18 from Northcote College.

Officials said they had contacted all but 18 of the 364 passengers on the first flight from Los Angeles, which carried the Rangitoto College swine flu suspects. All passengers who arrived in New Zealand Tuesday morning on seven overnight flights from North America were vetted by medical staff and cleared. (dpa)