A left-leaning think tank says the federal budget would be more than $13 billion better off if the Government scrapped all tax breaks on superannuation and dramatically increased the age pension.

The radical proposal is contained in a report by the Australia Institute, which will be released today, and comes amid increasing speculation the Coalition is preparing to increase the retirement age to 70.

"There is nothing in the budget that's going to grow faster than the tax concessions for superannuation," said the report's author Richard Denniss.

"It's the big elephant in the room. If we talk about the pension ballooning, well this is the Hindenburg."

The age pension and superannuation tax concessions are two major ways the Commonwealth helps retirees, but the policies are getting more expensive as Australia's population gets older.

"We're looking at around $70 billion in combined cost now with an estimated $100 billion in combined cost by 2020," Dr Denniss said.

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"Superannuation concessions are unfair ... the top 5 per cent of income earners get a third of the benefit, and the bottom 20 per cent get literally nothing."

The report suggests scrapping concessions entirely, introducing a universal or non-means-tested age pension and upping the current rate by about 7.5 per cent to $26,273 a year for singles and nearly $39,611 for couples.

The Australia Institute says that plan would cost about $52 billion annually, leaving the budget between $13 billion and $22 billion better off. It says more money would flow to women and poor people.

"You often hear people say the more people spend on superannuation tax concessions, the more we save on the age pension," Dr Denniss said.

"In theory that's possible, but in practice it's just not the case. If it were the case, the combined cost of these two schemes would be flat-lining."

The Australia Institute has long campaigned on superannuation tax breaks.

Its plan would hit high income earners, reduce the incentive for people to top up their superannuation and probably lead them to put more money into other investments with significant tax breaks, such as property.

"I don't expect all our proposals to be taken up ... but the general public and the Government need to start seriously talking about superannuation concessions," Dr Denniss said.

"The report makes it clear ... this issue is too big to avoid."

The idea is also likely to be fiercely opposed by superannuation funds.

The Financial Services Council says it will review the modelling and assumptions in the report before it comments.