HMRC repaid £31.1m during the first quarter of 2019 to more than 12,500 people, according to the latest figures.
This represents an increase of the overpayments when compared with the final quarter of 2018 when the tax authority repaid £30.2m to nearly 14,000 people.
Overall, HMRC has repaid more than £433m to taxpayers since the introduction of the pension freedoms.
Tom Selby, senior analyst at AJ Bell, said: "Given the ever-growing number of people affected by HMRC’s approach it is now imperative a thorough review – including input from those on the frontline – is initiated to find a better way forward."
HMRC stated in a newsletter published last June it had been reviewing the process for flexible pension drawdown payments, but it had concluded "that any changes at the current time would not significantly improve the tax position for the majority of recipients of a flexible drawdown payment, when compared to the process currently in place".
It had been urged to look at ways to fix the problem by the Office for Tax Simplification.
