Free vaccines will be available from next March for pregnant women, the morbidly obese and children aged between six months and four years who were enrolled in high deprivation general practices.
It is already available free to people over 65 and those aged six months to 64 years with certain health conditions.
Other people can get the vaccination through their doctors but will have to pay for it. Some employers provide workers with the vaccine.
Mr Ryall said the extension of the vaccine was part of an attempt to contain the swine flu pandemic.
There would likely be an upsurge in swine flu cases next autumn, he said.
"It is possible that another wave will occur in New Zealand before winter." The vaccine extension will cost an extra $2 million over the regular $14m annual cost.
If the pandemic became more severe before March, the Government had a contingency plan to immunise front-line workers, Mr Ryall said.
