New Zealand Prime Minister John Key says airport officials responded well to a health scare on board an Air New Zealand flight from Japan on Monday.

Passengers aboard the morning flight from Tokyo were not allowed to leave the airport for four hours after 73 Japanese students exhibited flu-like symptoms.

Auckland hospitals were on standby and medical staff were called in to assess the health of the passengers, but the students were found to have common colds.

Prior to receiving an official report about the incident, Mr. Key told TV3's Firstline program:

"(I)t seems to me the officials took the right steps of action; they quarantined people, they recognised the health scare, they tested what virus they had, they made themselves comfortable that it wasn't a new strain of virus or seasonal flu... I think it's about the right thing to do."

Mr. Key further acknowledged that outbreaks of bird and swine flu in recent years had a big impact on international travel, Key said.

Auckland Regional Public Health Service clinical director Julia Peters said the captain of the plane alerted ground staff in Auckland of the Japanese group, who were sitting in the rear of the aircraft coughing and sniffling.

Auckland Regional Public Health Service clinical director Julia Peters said it had been important to assess the students carefully, as it was a matter concerning public health.

''I understand it seems a long time and it is frustrating but people need to understand that it's important in making these assessments to get the right answer.''

Ms. Peters also said it airports and country officials should look deeper into the issue of whether there should be exit screenings at international airports.

However, Environmental Science Research senior influenza scientist Sue Huang, who also heads the WHO influenza centre, said exit scans were very good in theory but difficult to implement.

Under New Zealand law, any reports received by New Zealand Air Traffic Control of health problems aboard an aircraft are passed on to the Auckland Regional Public Health Service, which in turn, manages the alerts in cooperation with the relevant public health unit.