Sugary drinks are more dangerous than high-sugar foods and are each year causing an estimated 184,000 early deaths across the globe, a new Kiwi study finds.

It's led health experts to call for a tax on sugary drinks as an urgent measure in tackling New Zealand's deadly epidemic of obesity, type 2 diabetes and rotten teeth.

Global experts had earlier debated whether taxes and other health measures should aim to reduce sugar in all foods or instead focus more sharply on sugar in drinks.

But University of Auckland researcher Dr Gerhard Sundborn and his team's latest study found sugar in drinks was the top health priority.

It carried a greater risk of causing harmful "metabolic changes" that lead to illnesses, such as obesity and diabetes.

"This is due to its concentration, quantity and the speed with which sugar is metabolised when consumed in liquid form rather than solid," said Sundborn, whose findings were based on a study of existing medical evidence from around the world.

New Zealand has one of the highest rates of child and adult obesity in the world.

Another "striking" find from the study was that the consumption of sugary drinks in New Zealand had risen between 2002 and 2016, while it had been steadily falling in the UK and US.

"Sales figures indicate New Zealanders are drinking less soft drinks but more juice, sports and energy drinks," the report said.

"The average daily intake in New Zealand in 2016 was 175mL per person, compared to 275mL per person in the UK and 460mL per person in the US."

Typical sports or energy drinks contained 27g of sugar - or about 7 teaspoons per cup of liquid - while "fizzy drinks" had 26g and sweetened teas and flavoured milks had 24g.

Research had also shown some children were twice as likely to see advertising for sugary drinks and junk food than they were for healthy foods.

"We need to learn from what has happened in the UK, Mexico, Philadelphia, Berkley, Tonga and the Cook Islands and tax sugary drinks as they have done already," fellow researcher Dr Simon Thornley said.

He said New Zealand's Government needed "to implement a tax on sugary drinks to address this issue".