We may think we're a pretty active bunch but an international study shows Kiwis are less banana and more couch potato.

Almost half of Kiwis are putting themselves at risk of serious disease by not getting enough exercise, according to research.

The global figures show almost 48 per cent of New Zealanders over 15 fail to do the recommended amount of exercise, such as brisk walking for at least 30 minutes five times a week.

The research published in British medical journal The Lancet this week says this sedentary behaviour is placing people at greater risk of heart disease, diabetes and some cancers.

Our trans-Tasman neighbours, Australia, are more active with 39 per cent failing to meet the defined level of activity.

The US is close behind on 40 per cent, while the UK, playing host to the Olympics this year, has 63 per cent of the population getting insufficient exercise.

Researchers used World Health Organisation data to compare 122 countries, representing 89 per cent of the world's population.

Bangladesh had the lowest levels of inactivity at five per cent while Malta had the highest, at 71 per cent.

Worldwide, about 1.5 billion people - a third of adults - and four out of five teenagers are failing to meet physical activity targets.

The study's lead author Dr Pedro Hallal, from the Federal University of Pelotas in Brazil, blamed the levels of inactivity on advances in technology, including motor vehicles, which changed the way people lived and work.

However, televisions, the internet and wireless devices also contributed to sedentary behaviour, he said.

A second study said inactivity caused about six to 10 per cent of diseases including coronary heart disease, Type 2 diabetes, breast and colon cancer worldwide.

Physical inactivity is responsible for about 5.3 million of the 57 million deaths in 2008 and is just as dangerous in terms of disease and life expectancy as smoking and diabetes, the study says.