A New Zealand study has found obese children as young as five are showing signs they're at risk of developing serious weight-related problems.

LISTEN ABOVE: Otago University Dean of Medicine, Professor Barry Taylor, speaks with Rachel Smalley

Published in the Journal of Paediatrics and Child Health, the study has looked at more than 200 children aged 4 to 16 years in Taranaki over 12-months.

The programme called Whānau Pakari involved regular home visits from a health professional.

Researchers found:

* 75 per cent had signs of inflammation, increasing long-term heart disease risk

* 40 per cent had physical signs of high risk for Type 2 diabetes

* 47 per cent had at least one abnormal liver function test

* 11 per cent had abnormal blood pressure

* 50 per cent snored four or more nights a week - suggestive of obstructive sleep apnoea.

Paediatrician and co-author of the study, Dr Yvonne Anderson, said increased risk factors for heart disease, for fatty liver and for Type 2 diabetes were highly concerning.

"What we were very concerned about was how often we were seeing them in young children.

"I think there's a perception out there that these children are carrying just a bit of excess weight, but actually, they've got risk factors for long-term problems, and some of these problems aren't happening in adulthood, they're actually starting to occur in childhood."

Nationally 85,000 Kiwi kids are obese.

Otago University Dean of Medicine, Professor Barry Taylor, told Rachel Smalley the study confirms the issue is growing.

"Now we're surrounded by so much food that the consequences are children are becoming overweight, and certainly 60 percent of adults are also overweight."

Professor Taylor said there's a range of contributing factors - there's now too many food choices, too much advertising, and the harmful use of digital technology.

"Children are exposing themselves to a lot of lights late at night, and that's probably affecting their sleep."

Additional reporting by NZ Newswire