The Government is trying to get more nurses and medical officers of health into Auckland to help deal with the swine flu alert.
Thirteen people in New Zealand are now classed as known cases of the virus, which first surfaced in Mexico.
Public health personnel are working around the clock and Health Minister Tony Ryall says they are looking very tired.
Mr Ryall says the national health co-ordination centre in Wellington is trying to get support to certain places: particularly Auckland where resources are stretched - including at Auckland international airport.
He says extra nurses are needed and medical officers of health, who are specialists in disease prevention in the wider community.
At least 10,000 travellers from North America land in New Zealand each week and there is now health screening for every flight.
In addition, the Healthline service says it's fielding a record volume of calls.
Earlier arrival date?
Mr Ryall says it is possible swine flu came into New Zealand before the infected students from Rangitoto College arrived back from Mexico last Saturday.
He says at least one person among the 96 suspected cases flew into Auckland from North America prior to 25 April.
The virus was confirmed in New Zealand on Tuesday. Thirteen people among the Rangitoto College group are classed as known cases.
All those who are suspected of having swine flu are being tested to see whether they have Influenza A, as a precurser to further testing.
Mr Ryall says earlier reports of 14 cases of swine flu have been reduced by one as one person is now known not to have come from Los Angeles but to have joined a flight to New Zealand in Samoa.
Order in Council
An Order in Council is now in place to help the Government respond to the outbreak.
The Order adds swine flu to the list of notifiable diseases and would enable the Government to invoke emergency powers if the outbreak escalates into a pandemic.
That would make it easier to impose compulsory quarantine.