Sinn Fein has said it will not give evidence before a Westminster committee investigating amnesties for republican fugitives.
Deputy First Minister Martin McGuinness said that, although the party had nothing to hide, officials would decline invitations to attend a Northern Ireland select committee hearing in London next week.
The committee is investigating revelations made earlier this year that three British governments since 2001 provided 228 IRA on-the-runs (OTRs) with letters stating they were no longer wanted for past crimes.
The other four parties in the Stormont government accuse Westminster and Sinn Fein of keeping the deal secret.
A separate inquiry by Lady Justice Heather Hallett was ordered by David Cameron after the collapse of a case against a man accused of the IRA's Hyde Park bomb in 1982 - an attack that killed four soldiers.
The prosecution of John Downey, 62, from Co Donegal, was halted last month when it emerged he was wrongly sent a so-called letter of assurance informing him the authorities in the UK were not looking for him.
Downey, who was wanted by detectives in London, had denied the murder of the four soldiers.
Mr McGuinness said: "Sinn Fein has clearly outlined our position on the issue of on-the-runs and despite claims to the contrary, neither this process, nor the agreements on which it was based, were secret or hidden.
"However, in the interests of transparency and in an attempt to minimise the damage to the peace process from a growing public controversy, Sinn Fein agreed to participate fully and willingly in the Hallett Review.
"To that end our party president Gerry Adams, (Sinn Fein national executive member) Gerry Kelly and myself met with the Hallett review team earlier this week and put Sinn Fein's position on this and other legacy issues on the record.
"We see no point therefore in Gerry Kelly attending the Westminster Select Committee into the issue."
Last month, Drew Harris, assistant chief constable of the PSNI, told the committee that almost 100 fugitives who were given "letters of comfort" are suspects in nearly 300 murder cases.
Laurence Robertson, chair of the Northern Ireland select committee, said he was "surprised" at Sinn Fein's decision.
Mr Robertson said he had received letters from the party on their position this afternoon.
"I am especially surprised that they say they are giving evidence to the Hallett inquiry," the Conservative MP for Tewkesbury said.
"It begs the question 'what is the difference?' and of course there is a big difference - one is in public and the other is in private.
"That is the only difference I can see and that is obviously something that they are uncomfortable with.
"We were giving them the opportunity to put forward their point of view in public. If everything is above board why not come in and discuss it?"