Wellington - Twenty-seven students from a New Zealand college orchestra and four teachers are being treated as suspected swine flu patients after some developed flu-like symptoms after a trip to North America, health officials said Friday.

Lindisfarne College in Hastings sent most of the boys home, but a number of boarding pupils were placed in isolation at the school's hostel, the Hawke's Bay District Health Board said.

All were offered courses of Tamiflu antiviral medicine and had samples taken to test whether they were exposed to the influenza A strain associated with H1N1.

Cabinet Minister Nick Smith revealed Friday that he gone into voluntary isolation and is taking Tamiflu as a precaution after developing a "wicked fever" on return from his honeymoon somewhere in Asia. The exact location of his trip was not disclosed.

The Ministry of Health reported Thursday night that New Zealand had three confirmed patients with H1N1 and another 13 probable cases, who have tested positive for influenza A.

There are another 111 suspected cases of people displaying flu symptoms who have been to Mexico or North America recently or were contacts of cases.

In addition, officials have identified 121 cases of people in voluntary isolation and taking Tamiflu because of contact with suspected flu patients.

The deputy director of public health, Fran McGrath, said all were showing symptoms "around the mild end of the spectrum" for influenza.

New Zealand pharmacies were allowed to start selling Tamiflu without requiring a doctor's prescription for the first time on Friday, but only to people showing flu symptoms and buying it in person.

The Health Ministry rejected pharmacists' claims that requiring the sick to come in person risked spreading the disease and said it wanted to avoid panic buying, which would run down stocks and create a black market for the product.