New Zealand Health Minister Tony Ryall confirmed on Sunday that there were 10 positive influenza results from testing carried out on 13 students from Auckland's Rangitoto College who returned from Mexico on Saturday.

Ministry of Health officials said there was no guarantee that these students had swine influenza but considered it likely.

All precautions were being taken to allow for this.

"However, I am also informed none of the affected patients are considered seriously ill, and most in fact seem to be on the road to recovery," Ryall said in a statement on Sunday evening.

The 10 students had tested positive for Influenza A.

The results would be sent to the World Health Organization laboratory in Melbourne to ascertain whether it was the H1N1 swine influenza, he said.

He did not know when the results would be known, but said given the global situation they would be treated with considerable urgency.

He encouraged other passengers on NZ1, the flight from Los Angeles the Rangitoto College students returned on, to consult with their family doctors or other health professional if they develop flu-like symptoms.

Middlemore Hospital had released Tamiflu to the Auckland Regional Public Health Service to treat the patients and people who had been in contact with them.

The Ministry was in contact with the WHO and was liaising with Australia in terms of their response.

The ministry was also working closely with Auckland Regional Public Health, district health boards and other Government agencies including MAF, Customs and the Ministry of Education.

It would keep New Zealanders informed of developments, Ryall said.

H1N1 influenza is a subset of influenza A.

An emergency decree has been declared in Mexico following the outbreak of a new flu virus suspected of killing 81 people there. The World Health Organization has declared the outbreaks of influenza-like illness in Mexico and four US states as a "public health emergency of international concern".

Twenty-two students and three teachers from Auckland's Rangitoto College were voluntarily being quarantined at home in Auckland on Sunday after returning from Mexico, many with flu-like symptoms.

The group arrived back in Auckland early on Saturday, when concerns were raised by a family doctor and a hospital specialist who treated them for flu-like symptoms.

Auckland health authorities earlier said 13 students and one teacher from a group of 22 students and three teachers were unwell, and one of the students is in hospital on the North Shore.

It said the others were in home isolation in Auckland and it's supporting them and their families.

New Zealand's Ministry of Health said it has set up a National Health Coordination Center in Wellington to monitor developments.

The Ministry's chief advisor for population health Greg Simmons said it has activated the early stages of its pandemic response plan.

Simmons added that pilots are always expected to be on the alert for flu-like symptoms in passengers, but that's especially so now.

He added that customs officers have been asked to look for signs of respiratory illness in those returning from areas overseas where there is potential for this swine flu to be transmitted.

New Zealand's Ministry of Foreign Affairs and Trade has issued a travel health notice for swine flu in Mexico, California and Texas.

The ministry is advising New Zealanders who have recently traveled to any of the areas, and who develop flu-like symptoms, to seek immediate medical attention.

Auckland Airport said it was keeping a watching brief on the situation, though Air New Zealand does not fly directly into New York or Mexico.

New Zealand-based animal disease consultant, Roger Morris, said on Sunday that New Zealand has stockpiles of the medication Tamiflu which appears to work against the current strain of influenza.

Morris said at this stage the virus seems to react to Tamilfu and any early cases which arrived New Zealand would be treated with the drug.

Morris said stopping travel movement around the world will not stop the virus spreading.

He added that there will be enough people incubating the disease who will get through the system and continue to spread it.

(Xinhua News Agency April 26, 2009)