Mr Mark Durkan has challenged the Sinn Féin president to a public debate on what the SDLP calls "the damage done" to the Belfast Agreement by proposals published by the two governments that republicans support.
He said Sinn Féin had "attacked the SDLP with spin in a desperate attempt to cover up what has been conceded to the DUP" on agreement.
This was in response to lengthy criticism of the SDLP by Sinn Féin's Newry-Armagh Assembly member, Mr Conor Murphy.
He derided the SDLP record on the agreement since 1998, accusing the party of backing repressive legislation, the suspension of the Assembly, water charges and plastic bullets.
"While the SDLP have been unhelpfully sniping from the sidelines, Sinn Féin have been defending the rights of nationalists, the equality agenda and all-Ireland architecture against the objective of the DUP to achieve such a veto," Mr Murphy said.
"The approach of the SDLP to a relatively small number of key issues demonstrates that they are increasingly directionless," he added.
Turning to the SDLP position on photographic records of decommissioning, he said: "Now they are also supporting the DUP demand that humiliation, a concept entirely contrary to any peace process and the Good Friday agreement, should become part a comprehensive deal to move us forward."
Yesterday Mr Durkan hit back. "Conor Murphy has attacked the SDLP's record with spin and untruths in an attempt to cover up what has been conceded to the DUP." He said his party would present its challenge to the British-Irish "Comprehensive Agreement" early next week.
Welcoming the prospect of IRA decommissioning and the DUP acceptance of power-sharing, Mr Durkan said: "The Comprehensive Agreement gives the DUP a veto over the appointment of nationalist ministers and the decisions of nationalist ministers." He said Sinn Féin should be worried more by this than by demands for photographic evidence of IRA decommissioning. Vetoes would "be used by the DUP time and time again to humiliate nationalist ministers and nationalist people," he claimed.
"It is humiliating for the Irish people, who voted for that [ Belfast] Agreement, to find that the DUP and Sinn Féin have negotiated a new, so-called 'Comprehensive Agreement' that diminishes their right to equality."