WELLINGTON (New Zealand) - NEW Zealand reported 12 new cases of swine flu on Sunday, the biggest one-day spike in cases since the first was confirmed in late April, raising the total to 55.

Deputy director of public health Dr Darren Hunt said that for the first time some of the cases are not linked to travel, a signal that there was community transmission in some areas.

'Although confirmed case numbers are still relatively low, they are steadily rising,' he said - a situation health authorities have expected.

Most of the cases have been mild, but Hunt still warned those with symptoms to stay away from work or school, and to be prepared to care for themselves at home.

The new cases were being treated with the antiviral drug Tamiflu - along with their close contacts - and were asked to quarantine themselves, he said.

The World Health Organisation says that 74 countries have reported nearly 30,000 cases of swine flu, including 145 deaths. -- AP