Health officials say swine flu will cause many more infections than normal winter flu and it will go on for months.
The Ministry of Health also says the number of confirmed cases has risen again on Tuesday to 653.
Radio New Zealand's health correspondent says the total is a major under-estimate as routine testing to determine swine from winter flu is no longer being done and most people are considered able to recover by themselves at home.
Officials say those caring for others should watch for signs that they may need further medical attention, such as shortness of breath, chest pain, blueness around the lips, and inability to keep fluids down.
Wellington still has most cases, according to the tally, at 209; followed by Canterbury on 183 and Auckland on 176.
A woman in her early 20s is in a critical condition in intensive care in Hawke's Bay Regional Hospital. Another woman is critical but stable in Wellington Hospital.