New Zealanders' continuing love affair with full-fat dairy products is contributing to the country's biggest killer ¨C heart disease.

An online heart health survey, conducted by Southern Cross Healthcare and filled in by more than 21,000 people, found one in five New Zealanders preferred full-fat milk and one in 10 preferred butter to margarine.

Other choices high in saturated fat included cheese ¨C nearly one in three ate four of more slices a week ¨C and icecream, with one in eight eating three or more scoops each week.

Auckland University epidemiologist Rod Jackson said he was surprised people who were motivated enough and interested enough in health to do the test were still eating a lot of saturated fats ¨C the biggest cause of high blood cholesterol and a key risk factor in cardiovascular disease.

New Zealand's heart disease death rate was three or four times higher than that of Japan, he said. "Their rate is what we should be aiming for."

Unrepentant dairy-eater Brent Bircher, of Christchurch, could not explain why he continued to prefer "blue" milk over "green" and to eat up to nine slices of cheese and 12 scoops of icecream a week.

"I don't know why. I just take life as I go," he said.

Drinking a full-fat milkshake yesterday, Bircher, 23, said there was no heart disease in his family and his work as a window cleaner meant he burnt off whatever he ate.