Northern Ireland First Minister Peter Robinson has accused Martin McGuinness of being in denial on how to make progress on contentious issues of parades, flags and the legacy of conflict.
The Sinn Féin Deputy First Minister has urged all parties to implement proposals drawn up by former US diplomat Dr Richard Haass following months of negotiations.
The DUP has expressed reservations and its leader Mr Robinson claimed his Stormont power-sharing partner appears to believe it is everyone else's duty to reach agreement on his terms.
Mr McGuinness told the BBC that unionist politicians have accepted his assessment that the Ulster Volunteer Force, the Progressive Unionist Party and the Orange Order in Belfast are acting as "one and the same thing".
The Orange Order has said Mr McGuinness's remarks were "entirely without substance".
However, Mr McGuinness said his analysis is shared by mainstream unionism.
Mr Robinson said: "The unhelpful and irrational comments made by Martin McGuinness will do nothing to take the negotiations forward.
"He is in political denial and clearly has an exaggerated view of what his role is within the process.
"He speaks as if it is every other party's requirement to move to his position - and if they do not then he considers it to be a lack of leadership on their part.
"He speaks as if he is not one of the parties but rather the controller and dictator of how the process will operate."
Sinn Féin and the SDLP have endorsed the draft plan published after Stormont talks broke up without agreement on New Year's Eve.
It includes new mechanisms for dealing with the past and parades and greater provision for victims of the Troubles.
The DUP and Ulster Unionist Party have been less happy.
Mr Robinson added: "Every party in the process has had to move in order to narrow the differences. It is his responsibility to show some leadership and work to reach agreement on outstanding issues.
"Again, Sinn Féin will not dictate the rules of engagement. They do not own the process. They do not control how it will function or what it will (or will not) consider, nor will they prescribe the timing.
"The five parties will, by consensus, agree all of those matters and if they fail to agree then it will be as much his fault that he could not reach agreement with the majority unionist community as it would be the fault of unionists that they could not reach agreement with nationalists."
He said republicans will not regulate this exercise.
"As the largest party in Northern Ireland we will not be shepherded into any structure that restricts our ability to conclude agreement on deal imperatives," the East Belfast Stormont MLA added.
"If Sinn Féin or any other party does not want to be part of a process that seeks to resolve outstanding issues they can walk away but that will display a lack of leadership on their part."