Unionists must be shown that power-sharing is far preferable to having British ministers implement policies over their heads, the annual Sinn Féin Bodenstown commemoration was told.
Senior party member Gerry Kelly said the IRA had provided "a golden opportunity to advance a new era in our long struggle. It is crucial that this opportunity be grasped by Republicans and opponents alike".
Mr Kelly, an MLA and member of the party's national executive or ardcomhairle, believed that "we are in the countdown to a united Ireland" and "our goal as Irish republicans is an Irish unity that is inclusive, that unionists will feel welcome in, that they are part of".
Renewed efforts to advance the peace process would be made in coming weeks.
"Republicans have taken hugely important decisions. It is time for others to respond in like manner."
He told the gathering at Bodenstown cemetery in Co Kildare, where Wolfe Tone is buried, that "the challenge is there not just for the DUP but more importantly for the British and Irish governments. The inescapable question for the DUP is whether they are prepared to join with the rest of us in sharing power.
"If they refuse then it is the two governments who must deliver on their commitments to jointly implement all other elements of the Good Friday agreement. Unionism must be shown that power-sharing is much more preferable than British ministers implementing policies over their heads which are detrimental to the lives of everyone living in Ireland, nationalist or unionist."
Giving the annual Bodenstown oration for the first time, Mr Kelly said many would be "angry that those opposed to change are being pandered to" but "our response lies in our strengths".
He said: "We will never again accept the status of second-class citizens, North or South. Neither will we ever impose second-class citizenship upon anyone else.
"But unionists too have responsibilities and this includes the need to break with sectarian politics. The politics of domination."
He added: "However, we are mindful that for many unionists the change we have embarked upon is a terrifying prospect."
