The British and Irish prime ministers arrived in Belfast on Friday to endorse a deal to give Northern Ireland its first justice minister in one of the boldest steps since the 1998 Good Friday peace agreement.
A deal on devolving police and justice powers from London was reached late on Thursday after some 130 hours of tense debate, spanning nearly two weeks, between Sinn Fein and the Democratic Unionist Party (DUP).
Failure to get a deal would almost certainly have triggered a snap election in the British province where former foes, the predominantly Roman Catholic Sinn Fein and the mainly Protestant DUP, share power.
Britain's Gordon Brown and Brian Cowen of Ireland arrived in Northern Ireland shortly after 0800 GMT on Friday. They were expected to hold round table talks with the Northern Ireland parties and then a news conference around 1000 GMT.
The British and Irish prime ministers last flew into Northern Ireland at the start of last week and spent three days there brokering crisis talks.
The 1998 agreement mostly ended three decades of sectarian violence that cost 3,600 lives. Analysts had warned any political vacuum following a break down of talks could have led violence to flare up again.
Sinn Fein wants to see Northern Ireland united with the Republic of Ireland, while the DUP wants it to remain part of Britain.