The Parole Board has said it may have to deal with three times as many hearings next year, following a court ruling on fairness for prisoners.
The number of oral hearings could increase from 4,500 to 14,000, according to the Parole Board for England and Wales' annual report.
A ruling in October by the Supreme Court stated that the issue of giving a prisoner an oral hearing to determine their possible release or move to an open prison is different to assessing whether that prisoner is likely to be released or transferred.
The board's chairman Sir David Calvert-Smith said: "The implications of the decision, put simply, are that the Parole Board will have to hold oral hearings in a huge number of cases which had previously been dealt with on paper."
Just before the ruling the board claimed its case backlog had been at its lowest level for five years, but chief executive Claire Bassett said the judgement is "already having a profound impact on the volume of work handled by the Parole Board".
Justice minister Lord Faulks told the BBC the Government was working with the Parole Board to ensure it was able to cope with extra hearings following the court's decision.
"The board has been given an additional £3 million funding to enable them to handle any increased workload, and is also introducing a number of changes to improve their capacity," he said.
"Together with the board we will look at further options to help them deliver an effective service in this and future years."