Pension freedoms could generate tax revenue of around £19.2bn over the next decade, according to research from the Pensions Policy Institute (PPI).
In its research briefing note called How will the evolving retirement landscape impact tax and benefits?, the PPI has suggested HM Revenue and Customs had seen an increased tax revenue of at least £1bn a year.
The research showed 21 per cent of pension pots worth between £50,000 and £99,000 which had been accessed since the introduction of pension freedoms in April 2015 had been annuitised.
According to the PPI, the amount someone with £50,000 in defined contribution (DC) savings, £2,000 in defined benefit (DB) entitlement and a state pension of £164 a week would pay in tax could vary wildly depending on how they accessed their savings.
Their cumulative tax bill over retirement could vary between £110 if they withdrew 75 per cent steadily and ringfenced 25 per cent for a bequest but could increase to £7,378 if they withdraw their pot in full at state pension age.
Since the introduction of pension freedoms, 30 per cent of drawdown is bought without advice, compared to 5 per cent before.
Lauren Wilkinson, policy researcher at the PPI said "There is considerable uncertainty around the impact that pension freedoms may have on tax and means-tested benefits in the future, both in terms of individual impact and what this might mean for state finances on an aggregate level.
"Based on the way in which people have so far accessed their savings since the pension freedoms were introduced, HMRC could see increased tax revenue of around £19.2bn over the next ten years.
"Although some of these increases will result from the fact that people are increasingly reaching retirement with higher levels of DC savings, which means they may be offset by higher levels of tax relief received during the accumulation phase."
The research suggested tax payments will continue to increase because more people have been withdrawing from their pensions since the pension freedoms were introduced.
The PPI's research paper came after adviser platform Nucleus warned advisers they needed to consider whether they had the capacity to cater for the growing market, as more people opted for drawdown in retirement instead of buying an annuity.
The Work and Pensions select committee has called for capped drawdown fees but the Financial Conduct Authority's chief executive Andrew Bailey said he was not convinced it was the right thing to do.