The Northern Secretary, Mr Peter Mandelson, has called on the IRA to allow further inspections of its arms dumps by the independent arms inspectors.
While he was satisfied that the arms were "safe and secure", further inspections were necessary as a confidence-building measure, Mr Mandelson added.
Speaking on the BBC's Breakfast With Frost, the Northern Secretary confirmed that the two independent inspectors, the former Finnish president, Mr Martti Ahtisaari, and a leading member of the African National Congress, Mr Cyril Ramaphosa, had not carried out any more inspections since their first inspection of some IRA arms dumps in June.
"The original understanding and agreement was that the initial opening of dumps - that very important confidence-building measure - by the Provisional IRA should continue and that the dumps should be re-inspected. I hope that will happen shortly and that people will remain committed to the arrangement that they originally made," he said.
"They - the weapons - are, I am satisfied, safe and secure but it is important for people's confidence that this arms issue is properly being addressed".
The UUP's security spokesman, Mr Ken Maginnis, echoed Mr Mandelson's call. "It is imperative that despite other unfortunate distractions the objective of the Belfast Agreement is kept in view and progress is maintained," Mr Maginnis said. "The slowing down or failure to implement every aspect of the Belfast Agreement will jeopardise the whole process."
The anti-agreement Ulster Unionist MP, Mr Jeffrey Donaldson, said there seemed to be "no significant contact" between the IRA and the head of the International Commission on Decommissioning, Gen John de Chastelain. "This is totally unacceptable and it renders the continued participation in government of Sinn Fein/IRA in Northern Ireland in doubt."
Mr Donaldson said loyalist groups, too, had obligations under the Belfast Agreement to decommission their weapons and must not be "let off the hook".
Meanwhile, Sinn Fein has reacted angrily to remarks by Mr Mandelson and by the North's First Minister, Mr David Trimble, on policing reforms.
In speeches to the British Irish Association in Oxford on Friday, Mr Mandelson said that "absolutist" nationalist demands on the implementation of Patten could "imperil the wider political project".
Mr Trimble said the reforms had the potential to "deal a fatal blow" to the Belfast Agreement. A Sinn Fein MLA, Mr Gerry Kelly, yesterday accused Mr Trimble of "scaremongering".
Mr Kelly said the First Minister's comments came as no surprise given that unionism wanted the retention of what they saw as "their police force".
There has been speculation that the Irish Government has also expressed its unhappiness about Mr Mandelson's remarks. A senior Government source is reported to have told the Observer that Sinn Fein and the IRA would renege on further decommissioning if the report was not implemented in full.
The Sinn Fein chairman, Mr Mitchel McLaughlin, said he would be "very strongly" challenging Mr Mandelson's proposals on flags.
The Northern Secretary has tabled draft legislation specifying that the Union flag should be flown over designated public buildings, including departmental offices occupied by Sinn Fein ministers, on 17 specified days.
At a party ardchomhairle meeting in Dublin on Saturday, Mr McLaughlin said the proposals were "insulting to nationalists".