Martin McGuinness said he believed IRA denials over the robbery

He again said he believed IRA denials they were involved in the robbery, which police have blamed on the IRA.

Mr McGuinness said: "If the IRA had been involved...there would have been a defining moment in Sinn Fein's leadership's work with the IRA.

"It would have been totally and absolutely unacceptable to me."

The Democratic Unionist Party has called for the removal of allowances and privileges at Westminster from Sinn Fein's four MPs.

It follows an assessment by the PSNI Chief Constable Hugh Orde that the IRA was behind the raid on the bank head office in Belfast on 20 December.

Mr McGuinness told the BBC's Breakfast with Frost programme on Sunday that no-one in the Sinn Fein leadership had any knowledge of the raid.

Millions of pounds were stolen from the bank on 20 December

He added: "I don't see how it could have been in the interests of the IRA, who have made such a powerful contribution to the peace process going way back to their cessation in 1994, to be involved in such a risky operation, which would have undermined the republican contribution to a vitally important peace process."

On Saturday, the SDLP MP Eddie McGrady said his party should examine the possibility of entering a coalition without Sinn Fein at Stormont.

Eddie McGrady said his party should consider its options, and that nationalist voters had been "betrayed" by the IRA.

In response, Sinn Fein South Down MLA Caitriona Ruane called for SDLP leader Mark Durkan to clarify his party's position.

She said Mr McGrady's comments would "infuriate and anger" the vast majority of nationalists and republicans.

Ulster Unionist leader David Trimble has said republicans should not be given a last chance to join the political process.