The Stormont Assembly elections this Wednesday represent a "point of reckoning" for Northern Ireland, Taoiseach Bertie Ahern said today.
Speaking to the British-Irish Inter Parliamentary Body in Dublin, Mr Ahern insisted there will be no extension of the March 26 thdeadline for the restoration of the Northern Executive.
But he also held out the possibility of an improved economic outlook for the six counties if the St Andrew's Agreement were honoured.
The DUP have yet to commit to forming an administration with Sinn Fein despite repeated warnings from the Irish and British governments that a "Plan B" will be implemented over the heads of local politicians if the deadline for restoring devolution is not met.
Mr Ahern noted that the deadlock over Sinn Féin support for policing in the North had now been overcome and said the people of the North wanted their political representatives to govern together.
The Taoiseach said: "An Executive must be formed on March 26. This is the end of the line.
"It would be unconscionable and deeply regrettable if this agreed deadline was missed and if the opportunity to govern was not taken. Patience has already been stretched and I do not believe that the people would take kindly to further delay.
"The war is over. The key issues are sorted. All must take responsibility in government for building and consolidating the peace.
"We are now at a point of reckoning in the political process."
Failure to form an Executive as envisaged in the St Andrews Agreement would be a missed opportunity of historic proportions. Such a failure would see the newly-elected Assembly dissolved indefinitely."
Mr Ahern said the Government was committed to investing in the North "without a hidden agenda" and outlined some details of the cross-border package which is being finalised over the coming weeks.
Senior Irish and British officials are due to meet later this week to continue work on co-ordinating the funding.
The British have committed stg£50 billion in funding with the Republic adding a further €1bn for infrastructure and all-island co-operation in areas such as social inclusion, tourism and education and research.
"This year, for the first time, the new National Development Plan proposes significant Irish Government investment in projects and initiatives of mutual benefit North and South. "We want to see road links to Derry and Letterkenny that are second to none on the island. We want to build up the capacity of higher education institutions, through strategic alliances.
"The Northwest is a key example of where this is crucial to prosperity. In the Northeast, we want to see better links between counties Louth and Down to maximise the enormous tourist potential of the region."
The British-Irish Parliamentary Body consists of members from the Dáil, the House of Commons, the Northern Assembly, the Scottish Parliament the Welsh Assembly and the Isle of Man Parliament.