Sinn Féin has called on the DUP to begin direct negotiations with republicans and called on the British government to push ahead with justice and human rights reforms.
In a wide-ranging speech to party representatives from North and South at the weekend, Mr Mitchel McLaughlin reacted to the DUP's recent devolution proposals and denounced the British government for "undermining the agreement". Speaking in Co Meath, he insisted Sinn Féin's purpose was to unify Ireland.
Turning attention to the Rev Ian Paisley's party he said: "I say to the DUP - if you believe that remaining in the union with Britain in a constant state of dependency presents the best option then show some leadership and convince those of us that have a different perspective of the strength of your argument. If you are confident of your analysis then let the debate begin."
But he questioned the logic of the DUP position about direct talks with republicans before applauding the party for what he called a policy shift over power-sharing.
Mr McLaughlin said the party's document on devolution released 10 days ago represented a move away from traditional DUP thinking.
"The DUP proposals launched last week are a shift by that party from the never-never land politics that it has inhabited since its inception."
He dismissed two options for devolution put forward by the DUP as non-starters. These included the devolution of power to the Assembly, without an executive; and the formation of a "voluntary coalition" which could only include Sinn Féin in the event of the standing down of the IRA.
However, Mr McLaughlin said the third option held merit.
"The third is in their own imitable way recognition by the DUP that power-sharing government is the only way forward. This option is I believe a shift and it brings the DUP into the ballpark of the Good Friday agreement politics. They're in the ballpark - now let them become players."
The Sinn Féin chairman said British failures to uphold the agreement and to follow through with justice and human rights provisions has damaged the accord.
Mr McLaughlin's remarks coincide with Sinn Féin proposals to restructure the Stormont executive, creating three new departments and merging others to keep the total number at 10.
The DUP last night responded to the McLaughlin speech, dismissing his ideas until the IRA was done away with.
Mr Robin Newton, as East Belfast assembly member, said: "Republicans need to start addressing the real issues of guns, bombs, paramilitarism and gangsterism before pushing forward proposals for restructuring government. As unpalatable as it might to be to Sinn Féin/IRA, the terrorist organisation has to go away and go away for good."
He added: "They need to get real and address the necessary conditions for a restored, effective and stable devolved administration. Making proposals without addressing the weapons of mass destruction issue is just plain conceit."