Cancer Council Tasmania deputy chief executive Kathryn Terry said yesterday that 16 teaspoonfuls of sugar in a regular 600 millilitre soft drink was a ``lot of empty kilojoules''.

It equates to more than eight teaspoons of sugar in this 375 grams of a popular soft drink.

``What is particularly concerning about sugary drink consumption is that the quantity of sugar consumed is so excessive that it can be difficult for people to burn off the extra kilojoules,'' Ms Terry said.

Ms Terry was speaking after the national launch of a campaign, called Rethink Sugary Drinks,  to be run in conjunction with Diabetes Australia and the Heart Foundation.

The campaign will tackle one of the key contributors to obesity in Australia: sugary drinks.

Campaign organisers found that, based on US estimates, consuming one 600 millilitre container of soft drink a day could lead to a 6.75 kilogram weight gain in one year.

In the year to October 1 last year, Australians bought 1.28 billion litres of carbonated or still drinks with sugar.

Regular cola drinks were the most popular with 447 million litres consumed annually. Ms Terry said that the Cancer Council wanted Tasmanians to rethink their sugary drink consumptions.

``We recommend that adults and children limit their consumption and rehydrate with water as their drink of choice,'' she said.

The Rethink Sugary Drinks campaign is the first time that the three leading Australian health organisations have joined forces to release recommendations on the sale of sugar-sweetened beverages such as soft drinks in an attempt to tackle obesity rates.

The organisations have called for immediate action by governments, schools and non-government organisations such as sports centres to tackle sugary drinks.

A recent survey by the Cancer  Leg 1?Council and Heart Foundation found that one in five secondary schools in Australia had vending machines - 49 per cent of which contained sports drinks and ?jl38 per cent soft drinks.