New Zealand is on the brink of declaring a public health emergency, after confirming three cases of swine flu in people who contracted the virus in New Zealand.

The first two confirmed cases of community transmission of Influenza A (H1N1) were recorded in the Wellington region yesterday morning. An Auckland case was confirmed soon after, in a child at ABC Learning Centre in Meadowbank.

Three more cases were also identified around Wellington, but the Ministry of Health was still trying to ascertain whether they contracted the virus as the result of travel.

The development is significant as they are the first cases of the virus being contracted in New Zealand rather than by travelling overseas.

The Meadowbank child was the second at the childcare centre to test positive for the virus. The first child had returned from an overseas trip.

Deputy director of public health Dr Darren Hunt said the community transmission stage had come two months earlier than expected, and showed the first signs of what was likely to be a much wider spread.

Nationwide there were 43 confirmed cases of Influenza A yesterday, up by nine from 34 on Friday.

With the number of cases increasing daily in Australia, Hunt said New Zealand would also see an increase. "It's certainly not anticipated it will go away next week."

Hunt said New Zealand was at a "containment" phase. Other centres around the country might not see the same spreading pattern as Wellington and Auckland.

The Wellington swine flu sufferers are being managed in the community by public health staff, and recovering well at home.

Meanwhile, the Ministry of Health has not asked people to cancel or postpone overseas travel during the school holidays which start on July 4.

On Thursday the World Health Organisation (WHO) declared the Influenza A swine flu outbreak as a pandemic and moved to alert 6 in recognition of the global transmission of the virus.

The Ministry of Health has moved its pandemic response status to Phase 6 - 6.2 Code Yellow. Under the pandemic plan, this stage can include declaring a public health emergency at a local or national level and restrictions on our borders. Phase 6.2 includes isolating affected areas of the country, restricting public gatherings and closing educational facilities.

Clinical director of the Auckland Regional Public Health Service, Dr Julia Peters, said these new cases could require school closures.

"We're probably close to those sorts of measures," she said.

As well as the second confirmed case at the ABC Learning Centre, 12 other children with flu symptoms have had swabs taken and are in quarantine.

"We will continue to do what we're doing, which is trying to slow it down and to lessen that peak so we have it over a longer period," Dr Peters said.

The Ministry of Health is advising the public to prepare to be self-sufficient for an extended period by having enough food and water and basic medical supplies, including paracetamol.

Because this is a new virus, there is no immunity to the disease. A vaccine is not expected to be ready until September, for the northern winter.