Gerry Kelly accused the government of trying to buy off the DUP
The government is to make a £20m payment to former members of the police part-time reserve in Northern Ireland.
Sinn Fein's Gerry Kelly said the offer was contained in a letter to the DUP leader Peter Robinson which they obtained by mistake.
The letter from the prime minister was sent to the Office of the First and Deputy First Minister.
Mr Robinson said he had wanted to wait until he had met with former part-time reservists before publishing details.
"A meeting has been arranged with the reservists for early next week about this proposed scheme and how it could best be implemented," said Mr Robinson.
"I want to be sure their views are fully considered and reflected when the scheme is rolled out.
"I have long felt it was unjust that part-time reservists had been neglected and not given due recognition."
Mr Kelly, a junior minister, said it was a government attempt to "buy off the DUP".
He said that when the issue was raised by Gordon Brown during negotiations over the budget for devolving policing and justice powers, Deputy First Minister Martin McGuinness of Sinn Fein told him such payments would be wrong and unacceptable.
Mr Kelly said Sinn Fein would not allow the DUP to make pre-conditions on devolving policing and justice.
"They talk about confidence - how is that going to bring confidence?" he said.
"When they talk about community confidence, they are only talking about one section of the community - they don't care if they annoy nationalists and republicans."
Earlier this month, Mr Brown published budget proposals for the devolution of policing and justice.
Sinn Fein has already approved the deal - believed to be in the region of £800m to £1bn - but the DUP say the unionist community must have confidence in any proposed arrangements before devolution happens.
It is understood the demand was contained in an eight-page letter given to Mr Brown by the DUP during negotiations.
It is believed as many as 9,000 former part-time reservists could benefit from the money.
A spokesman for the Police Federation said they would welcome any recognition of the contribution made by the part-time reserve since 1970.