The Government plans to send senior officials to meet their Northern counterparts next Friday if the North's First Minister blocks the participation of the Sinn Fein Minister, Ms Bairbre de Brun, in a planned ministerial meeting.
A Government spokesman said last night that the Taoiseach was determined that "some meeting" would take place next Friday, the day the Minister for Health, Mr Martin, is scheduled to meet Ms de Brun, his Northern counterpart.
The Government's statement of intent came as Sinn Fein, strongly and at times angrily, pressed the Government to defy the Ulster Unionist Council decision to block Sinn Fein participation in meetings of the North-South Ministerial Council. Next Friday's scheduled meeting would be the first to be affected.
The other Sinn Fein Minister, Mr Martin McGuinness, yesterday challenged the Irish and British governments to "defend the agreement" against the unionist tactics.
Sinn Fein sources said Ms de Brun did not intend to change her schedule, which includes attendance at the Friday meeting in Enniskillen. They added pointedly: "That meeting is not just a matter for David Trimble. It is a matter for Dublin also."
As the Government and nationalist parties considered how best to respond to Mr Trimble's tactic, it emerged that the Taoiseach had decided that "some meeting" should take place to show that the work of the North-South Ministerial Council was continuing.
While this is the current position, sources conceded last night that what would transpire on Friday was still uncertain.
Should Mr Trimble's action mean that a meeting of the North-South Ministerial Council cannot legally take place, it appears likely that the Government will attempt to send some of Mr Martin's senior officials to meet their Northern counterparts.
The meeting would not legally be a meeting of the North-South Ministerial Council, but would nevertheless discuss the business that would have been transacted between the two Ministers.
It was not clear last night whether Sinn Fein would accept this position as an alternative to sending Ms de Brun herself.
The Taoiseach held a lengthy telephone conversation with the British Prime Minister last night, and the Minister for Foreign Affairs, Mr Cowen, met the North's Deputy First Minister, Mr Seamus Mallon. Meanwhile the Northern Secretary, Mr Peter Mandelson, had talks with the Sinn Fein president, Mr Gerry Adams.
Mr Mandelson will travel to Dublin this week for discussions with Mr Cowen. Mr Mandelson is expected to press the Government to agree to a greater role for the Independent International Commission on Decommissioning, as demanded by Mr Trimble.
Mr Trimble is seeking the full re-engagement of the IRA with the commission, following which that body would produce monthly reports on the nature of that engagement and on progress made.
The Government, however, is to continue to press for the full implementation of the Patten report on police reform, for greater British demilitarisation, and for continued progress on equality and human rights issues.
In its statement last week the IRA said it would not re-engage with the decommissioning body until the other aspects of the agreement were implemented.
The Government's aim is to ensure that as many as possible of those aspects are dealt with so that pressure could be exerted on the IRA to re-engage with the de Chastelain commission.
Sinn Fein demanded an emergency meeting of the Northern Ireland Executive and urged both governments to take action to defend the Belfast Agreement.
A senior party source signalled determination to resist the Unionist move. "Our Ministers will continue doing their jobs and will not be put off by David Trimble's antics."