Gerry Adams' call for unionists to compromise on parades and the past is "a bit rich", according to the DUP's Sammy Wilson.
The squabble comes ahead of expected talks to try to resolve disputes over flags, parades and the legacy of the past.
The Twelfth has been plagued by violence in recent years over disputed parades, particularly in north Belfast.
But despite the height of the marching season looming large, no start date for talks has yet been set by Peter Robinson and Martin McGuinness. And instead of setting out their stalls, the two main parties bickered at the weekend.
The East Antrim MP said Mr Adams' plea couldn't be taken seriously while Sinn Fein continued to oppose peaceful parades and Mr Adams continued to deny his role in the IRA.
The Sinn Fein leader had earlier told a Dublin party conference there is "widespread concern about the situation within the DUP".
"It is quite clear that the DUP does not appear to have the appetite for the challenge of dealing with the outstanding issues of flags, parades and the past in any serious way," Mr Adams said.
"For any process aimed at resolving these issues to succeed unionist political leaders need to show a similar willingness. That has not been evident so far."
But Mr Wilson said there was no sign of Sinn Fein telling the truth about the past and showing tolerance for loyal order parades.
"The unionist community feels it's a bit rich for Gerry Adams to demand compromise whenever he refuses to give an inch on parading or the past. Words come cheap.
"It's time he put his words into action and practiced what he preached.
"Where is the compromise from Sinn Fein?" he said.
"Rather than call for others to compromise, Gerry Adams should set an example and demonstrate tolerance of loyal order parades and tell the truth about his past. Then he could expect to be taken seriously."