The Ulster Unionists have pressed the British government to recall the Assembly with a view to having political sanctions levied against Sinn Féin.
Mr David Trimble said he had pressed Mr Tony Blair to resort to what he called "quite savage, quite significant" powers against Sinn Féin.
This follows last week's Independent Monitoring Commission report which alleged IRA and Sinn Féin involvement in the Northern Bank robbery.
Mr Trimble wants Assembly members to be summoned to a restored Stormont to debate the exclusion of Sinn Féin from the Executive.
He also wants the Northern Secretary, Mr Paul Murphy, to outline such a move when he makes a statement on the IMC report to the House of Commons next week.
That report recommended financial penalties but also said it would have called for political exclusion were it not for the suspension of Stormont.
Ulster Unionists are keen for what a spokesman called "centre parties" to regain political momentum following last December's failed attempt to get Sinn Féin and the DUP to agree terms for the restoration of devolved government. Mr Trimble will be lobbying support for his position in Dublin today having visited London last night to push his case.
According to the SDLP, the British Prime Minister, Mr Blair, has already pressed Mr Mark Durkan to consider an arrangement with the Ulster Unionists.
Yesterday he said legislation enacted in 2003 laid down clearly how the exclusion of Sinn Féin could be organised.
If the recalled Assembly failed to pass an exclusion motion the British government should then use its own powers to exclude Sinn Féin and allow the other parties to continue without them.
"The teeth are in this process and have to be used. If the Secretary of State does not announce that next Wednesday then I think huge damage will be done to his credibility, the government's credibility and the process as a whole," Mr Trimble said.
In the US, Mr Durkan meanwhile claimed that politicians there want to "stand tough against paramilitaries and stand strong for the Good Friday agreement".
Mr Durkan has hosted a round of briefings of key senators and congressmen ahead of a reception hosted by Senator Edward Kennedy to honour Mr John Hume before his retirement from Westminster in May.