"We've won the war. Now let's win the peace," the veteran republican, Mr Joe Cahill, told Sinn Féin's ardfheis at the RDS in Dublin.
His presence and short speech won a sustained, standing ovation from delegates.
Mr Cahill effectively launched the Northern Ireland Assembly election campaign, warning delegates that the next eight weeks would be crucial.
It was their duty as republicans "to ensure the Sinn Féin's vote is larger than ever before and the opportunity presented by our negotiation team is seized. Anything less would be unforgivable".
A number of motions and delegates were critical of the Government, calling for it to be more pro-active in implementing the Belfast Agreement and for action on sectarian attacks.
Just one motion passed was critical of the Sinn Féin leadership, expressing the deep concern of the grassroots at the lack of information from the leadership during talks.
Mr Tommy Williams, from Ardoyne in north Belfast, the only speaker on the motion, said in a short, mild address that while people understood the difficulties the leadership faced, "we feel that as much information as possible" should be given to the grassroots.
Party vice-president Mr Pat Doherty warned that the party's progress in the past 15 years would be in vain "if we are not clear and agreed on the political project which we have undertaken".
They had to secure the "national, democratic and social rights of all sections of our people".
Unionism "needs to realise that human rights, equality, democracy or decent policing are not concessions", he said. "Sinn Féin won't be bartering on these issues. They are basic rights and basic entitlements and are the direct result of the outworking of the Good Friday agreement."
He added that unionists knew what full implementation of the agreement meant. "They know that a level playing field removes much of the rationale for the existence of unionism itself."
The party chairman, Mr Mitchel McLaughlin, said the party recognised the concerns about the continuing existence of armed groups.
"But we have made it clear that we will not accept the imposition of sanctions or pre-conditions that are outside the terms of the agreement, or are designed to deny the rights of the people Sinn Féin represents."
However, in an approach to progressive unionists, he said: "I can assure them that if they work in good faith with us, republicans will not be found wanting." To "those unionists who fear change, I say, rather than fight against the change that is happening, be a part of it, help manage it".
The party's North Kerry TD, Mr Martin Ferris, criticising the Government, said Fianna Fáil claimed to be a republican party. It had to begin to act as though it believed that "the British army has no more business being in Fermanagh than in Ferbane, Co Offaly, in Minister Cowen's constituency", he said.
