Wellington - The number of swine flu victims in New Zealand grew to 14 on Wednesday, but health authorities said all were recovering well and there was no need to panic.

Officials said there were 31 suspected cases in the country and another 179 people who may have been in contact with those affected were in voluntary isolation around the country and had been offered a course of Tamiflu antiviral medication.

"The numbers are going to change - it's an evolving situation," Julia Peters, clinical director of the Regional Public Health Service in Auckland, where all 14 confirmed cases are, told a news conference.

Officials added three more suspected cases to the 11 confirmed Tuesday night after tests at a World Health Organization regional laboratory in Melbourne, Australia, on samples from a group of college students who flew home Saturday to New Zealand via Los Angeles from a study trip in Mexico. One of the additional cases was another member of the group from Auckland's Rangitoto College.

The other two were recent visitors to Mexico or North America who had developed flu-like symptoms after returning home.

Health Minister Tony Ryall said that reports showed that 19 countries now had suspected cases of swine flu.

Public Health director Mark Jacobs said there was no need for panic, and the strain of swine flu identified in New Zealand had produced only mild symptoms in those affected.

The government, which has advised against all non-essential travel to Mexico, is asking anyone who develops flu-like symptoms after visiting that country or elsewhere in North America in the last seven days to seek medical advice.

All passengers flying into New Zealand from North America are being monitored by medical staff at airports and given information about the swine flu outbreak and what to do if they develop symptoms. Officials said the Health Ministry has enough Tamiflu on hand to treat a third of the population of 4.3 million, if necessary.