Around 40% of New Zealanders support the idea of introducing a tax on fatty foods to tackle the country's obesity problem, a poll has suggested.

In Auckland, support was even higher, with 47% of people thinking a tax would be a good idea, according to the National Business Review-Phillips Fox poll.

Dr Russ Finnerty, president of Diabetes News Zealand, expressed surprise at the result of the poll.

"The poll suggests that the continuing media exposure about fat and obesity has raised the awareness of the harmful effects of fat to the extent that a sizeable portion of the population might support legislation," Finnerty was quoted by the National Business Review as saying.

However, Liam Jeory, McDonald's director of corporate relations in New Zealand, said the results of the poll made him question whether people realised the ramifications of a so-called 'fat tax'. He said that dairy giant Fonterra would be hit by the tax as cheese and butter has a higher fat content than burgers.