A pensions advisory firm believes that the tax-free cash lump sum could be under threat.
The Institute for Fiscal Studies recently proposed the sum people can take when they retire should be restricted.
Bosses at Broadstone said this has given the idea greater credibility, despite being dismissed down the years.
{desktop}{/desktop}{mobile}{/mobile}
John Broome Saunders, actuarial director at Broadstone, the independent pensions and investment expert, said: "There must now be a big question mark over the on-going status of the 25% tax free lump sum.
"Tax-free cash has historically been the carrot to incentivise people to save for retirement – but with the roll-out of auto-enrolment, government pension strategy is moving from carrot to stick – meaning there's less need for such an incentive.
"Capping the amount of tax-free cash available – as suggested by the IFS – is one option. Alternatively, the Government could simply start taxing the lump sum, perhaps at a lower rate.
"This must be appealing to HM Treasury - a 20% tax on pension lump sums could raise an extra £1bn every year."