The SDLP has reiterated that it "believes in a united Ireland" and called for a referendum on the issue, in its Assembly election manifesto.
Party leader Mark Durkan said in working towards a united Ireland the party would engage in "outreach" with unionists.
He also called for the reconvening of the Forum for Peace and Reconciliation.
There was provision for a united Ireland plebiscite in the Belfast Agreement and it should be held when the agreement's institutions were operating stably, Mr Durkan said.
The SDLP would "campaign vigorously" for a vote in favour of a united Ireland.
He also called on Northern Secretary Peter Hain to make clear that, regardless of the DUP's position, he would attempt to reinstate the executive and Assembly on the St Andrews' deadline of March 26th.
"Peter Hain should be saying not so much that March 26th is devolution or dissolution, but that March 26th is devolution. That's the certainty that needs to be created.
"The DUP has to know that there will be devolution on March 26th and if they collapse things or mess things up to bring about dissolution, then people will know who to blame for this dissolution," he said.
Mr Durkan said that when the SDLP was strong, political progress was achieved. The choice for voters was between "stop-go politics and non-stop progress, delay and delivery and those who want only to bicker and those who are determined to build".
He described Sinn Féin and the DUP as the "suspension parties" whose ambitions were to be "king of the castle".
The SDLP manifesto calls for the harmonisation of 12½ per cent corporation tax with the Republic and the development of an all-Ireland economic policy unit.
It also calls for the decentralisation of at least 2,000 public sector jobs to towns across Northern Ireland.
Meanwhile, the Conservative Party in Northern Ireland at its manifesto launch yesterday in Belfast called on the Assembly "to deliver value for money" for the people of Northern Ireland.
The Conservatives - who are fielding nine candidates in nine constituencies, more than it has fielded before, including James Leslie, a former Ulster Unionist MLA - is largely campaigning on "bread-and-butter" issues.
"For too long our local sectarian, tribal political parties have focused on issues that simply are not important any longer," said Jeffrey Peel, vice-chairman of the Conservatives in Northern Ireland, at the launch.
People were fed up with what was on offer from local parties, who had no policy agendas apart from the Border.