British prime minister Tony Blair and Northern Secretary Peter Hain will this week attempt to impress upon the Rev Ian Paisley and the DUP that if devolution is not reinstated by March 26th the new Assembly will collapse.
Over the weekend Mr Hain rejected speculation, mainly from DUP quarters, that the British government would tolerate the formation of a shadow Northern executive on Monday week and that this would "buy time" so that devolution could be re-established by May.
With just two weeks to go to the March 26th deadline, Mr Hain will today and tomorrow conclude his initial meetings with the political parties, while Mr Blair is scheduled to have talks with the DUP leader, Dr Paisley, in London on Wednesday.
All 108 newly-elected MLAs are due to gather for the first time in the Stormont Assembly chamber tomorrow in "transitional form" to designate themselves as unionist, nationalist or "other". Senior Northern politicians, with the likely exception of Dr Paisley, will travel to Washington for St Patrick's Day, where the US administration will also bring pressure to bear for power-sharing.
Mr Hain warned yesterday that if the current opportunity for a historic DUP/Sinn Féin-led executive failed, it could be "years" before a similar chance presented itself.
If the new Assembly is dissolved, the governments have made it clear that direct rule will continue, but with an enhanced role for Dublin.
"We remain fully committed to the March 26th deadline," a senior London source said last night. "If March 26th doesn't happen, then that's it; the Assembly crashes and all 108 members will lose their pay and allowances. The only way back after that would be through another election. And when could that happen? People need to understand that."
Mr Hain is to meet Minister for Foreign Affairs Dermot Ahern at Hillsborough Castle this afternoon, where the two ministers will discuss the British and Irish governments' strategy.
A battle of wills between the British government and the DUP is in prospect over the next two weeks, with Dr Paisley already signalling that he does not consider himself bound by any deadlines.
Diaries permitting, Dr Paisley will meet Mr Blair in London on Wednesday, where the prime minister is expected to repeat the same points made by Mr Hain.
Writing in yesterday's London Observer, the Northern Secretary placed the British government in such a definitive position that it would be seen as abject weakness if it did not hold to its stance of "devolution or dissolution" by Monday week.
"There has been some speculation that the governments, so close to a deal, would allow for the formation of a shadow Assembly to keep the process on track. There will be no shadow Assembly . . . There is no discretion in this," Mr Hain wrote.
"Anyone trying to push devolution beyond March 26th or trying to stop devolution altogether will find that they will be left behind, perhaps for years, because who knows when there might be another opportunity to get the institutions up and running again."
Both governments are conscious of the fact that Dr Paisley faces tensions within his party over power-sharing. They are expected to try to ease some of that pressure with commitments to a financial dividend from British chancellor of the exchequer Gordon Brown, together with financial assistance already pledged by Minister for Finance Brian Cowen.
This issue is also likely to be high on the Hain-Ahern agenda at Hillsborough Castle today.