The Government was today accused of agreeing to pay former part-time police officers in Northern Ireland £20 million in a bid to secure political concessions from the Democratic Unionist Party (DUP).

Sinn Fein today produced a letter sent by Prime Minister Gordon Brown to DUP leader and Northern Ireland First Minister Peter Robinson making the multi-million pound offer.

Republicans claimed it was a bid to "buy-off" DUP support for the devolution of policing and justice powers from Westminster to Stormont and claimed government risked bringing the process into disrepute.

Sinn Fein and the DUP have been locked in talks with Mr Brown on efforts to transfer the powers that would effectively see unionists and republicans share responsibility for Northern Ireland's police and justice system for the first time.

"Yesterday I was given a letter from Gordon Brown to Peter Robinson indicating that the British government has decided to issue a gratuity payment of £20 million to former members of the RUC Part Time Reserve," said Sinn Fein Junior Minister Gerry Kelly.

"When Gordon Brown raised this issue with ourselves, Martin McGuinness told him that such a payment was wrong and unacceptable and was no part of the process to transfer powers on policing and justice."

The dispute over the devolution of the powers has threatened the stability of the power-sharing government at Stormont.

And while Sinn Fein has pressed for swift action on the transfer of powers, the DUP has said it wants to proceed with caution to ensure the process is properly stewarded.

The main unionist party, however, also faces pressure from hard-liners who are opposed to a deal which would give republicans any role in overseeing police and the courts.

Mr Brown has offered the parties a financial package estimated to be worth more than £800million to fund the devolution process, but while Sinn Fein has accepted his offer, the DUP has yet to do so.

Democratic Unionist leader Mr Robinson has called for the scrapping of the Parades Commission to help ease tension over marches ahead of the devolution of powers into the hands of local politicians.

Nationalists have, however, accused the DUP of trying to secure the scrapping of the commission for political reasons. The Parades Commission has restricted Orange Order parades in Catholic areas and its removal has been a long-standing demand of unionists.

Mr Kelly said the Prime Minister had previously sent a separate letter confirming his near £1billion funding package for devolution.

But he said the latest offer of funds for former Royal Ulster Constabulary part-time officers, understood to have missed out on earlier financial packages to former members of the force, was not included.

"The detail of the financial package agreed with the British Government between Martin McGuinness and Peter Robinson is set out in the letter from Gordon Brown to the parties," said Mr Kelly.

"This (further) payment forms no part of it. The effort to transfer policing and justice powers is being brought into disrepute by the British government's willingness to buy off the DUP.

"At a time of economic downturn, and huge pressures on working families and the disadvantaged this payment is a waste of taxpayers' money.

"It should also be remembered that this is the same British government which in the wake of the Eames/Bradley report quickly moved to veto a recognition payment to those bereaved through the course of the conflict."

Mr Kelly claimed the letter from Mr Brown to Mr Robinson was sent, apparently mistakenly, to the Office of First Minister and Deputy First Minister at Stormont.

This meant it was automatically copied to Sinn Fein's Martin McGuinness, who under the rules of the power-sharing government, shares the top political office with Mr Robinson.