Taxing sugary drinks is the first step in addressing New Zealand's obesity and diabetes epidemic, health researchers say.

A sweetened sugary beverage tax is gaining momentum as a public health measure and must be led by the government, says Professor Tony Blakely from the University of Otago's Department of Public Health.

A sugary drinks tax, specifically targeting the amount of sugar in each drink, came into effect in the UK on April 1.

Prof Blakely and his team have analysed the literature and recent reports and have written a blog about the health impacts this levy might have here in New Zealand.

They also refute a recent NZ Institute of Economic Research report that argued against taxing sugary drinks, saying it has "serious flaws".

Sugary drink taxes can be configured in many ways, Prof Blakely said, advocating the UK and its tiered soft drinks industry levy.

"It is clever, and its impact is much more than via the direct price signal to the consumer," he said.

A sugary drink tax would have a number of impacts and benefits including a price signal to consumers to reduce consumption and an incentive on the industry to change marketing to less sugary drinks.

Prof Blakely says a soft drinks industry levy is something that could be put in place right now in New Zealand, backing recommendations from the World Health Organisation, NZ Medical Association and the Heart Foundation.

"The government would be strongly supported by the scientific evidence if it did opt for a sugary drinks tax."