Celebrity chef Jamie Oliver has urged Australia to "pull its finger out" on tackling obesity after Britain announced a sugar tax on soft drinks.

The levy on drinks with more than five grams of sugar per 100 millilitres will be introduced in two years' time as Britain attempts to cut down on spiralling childhood obesity levels.

Chancellor of the Exchequer George Osborne announced the measure in his annual budget statement.

"We all know one of the biggest contributors to childhood obesity is sugary drinks," he said.

"I am not prepared to look back at my time here in this parliament, doing this job and say to my children's generation, 'I'm sorry. We knew there was a problem with sugary drinks. We knew it caused disease but we ducked the difficult decisions'."

Sugar per 100ml in soft drinks Solo - 12.1g

Solo - 12.1g Fanta - 11.2g

Fanta - 11.2g Red Bull - 11g

Red Bull - 11g Bundaberg Ginger Beer - 10.8g

Bundaberg Ginger Beer - 10.8g Coca Cola - 10.6g

Coca Cola - 10.6g Sprite - 10.1g

Sprite - 10.1g Vitamin Water - 5.49g

Vitamin Water - 5.49g Lipton Ice Tea - 5.3g

Oliver, who has lobbied tirelessly for a sugar tax, hailed the surprise announcement.

"We did it!" he said on Instagram, saying it was "a profound move that will ripple around the world".

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He posted a video on Facebook urging other nations including Australia, Canada and Germany follow Britain's lead.

"It's about time your governments got on this," he said.

"Australia, pull your finger out."

Greens leader Richard Di Natale said the new levy to be introduced in 2018 was a "really interesting proposal".

"Why can't we have a tax, that we know what it does is discourage unhealthy choices from people, and that money could be reinvested back into the health system?" he said.

Official data from last year showed 61.9 per cent of British adults and 28 per cent of children aged between two and 15 were overweight or obese.

Mr Osborne said the tax would have two bands — drinks with more than five and eight grams per 100 millilitres — and was estimated to raise $UK520 million ($967 million).

Britain's Office for Budget Responsibility, the Government's budget watchdog, said the figures implied a levy of 18 pence (34 cents) per litre, or 24 pence (45 cents) for those in the higher band.

Mr Osborne acknowledged the price rise might be passed on to consumers but said the money raised would be spent on funding school sport.

He said the delay in implementation would "give companies plenty of time to change their product mix".

Isabelle Szmigin, professor of marketing at the University of Birmingham, said "the challenge now will be whether the large soft drinks manufacturers will reform the contents of their products, rather than simply raising prices".

Farm lobby to resist sugar tax

Canegrowers Queensland chairman Paul Schembri said a sugar tax would "cascade" back to producers.

"We will do everything in our power to resist it," Mr Schembri said.

"We are quite confident that there isn't the political climate in Australia to have this tax introduced at this point in time."

Australia is the third largest supplier of raw sugar in the world, with annual production worth $2 billion to the national economy.

But Mr Schembri said a 2015 study found Australia's per capita sugar consumption had decreased by 16.5 per cent over the past 40 years — from 50.3 kilograms in 1970 to 42 kilograms in 2011.

"There's been this crusade ... to demonise sugar and we're not convinced that there is any substance to that argument," Mr Schembri said.

"If the per capita consumption of sugar is in decline, we are struggling to understand how it becomes the bogey man of all these health ailments."

Finland has had a similar levy since the 1940s, while France introduced it in 2012 and Mexico in 2013. South Africa will introduce one next year.

Denmark introduced a tax on Coca-Cola in 1953 as a protectionist measure to promote its own beer industry, but it will be scrapped next year.

ABC/wires