Arlene Foster's leadership of the Democratic Unionists remains a stumbling block that could scupper crunch talks to end a powersharing stalemate in Northern Ireland, Sinn Féin has warned.
Declan Kearney, the party's chairman, said a DUP focus on Ms Foster's future role at Stormont "is completely misdirected and premature".
Referring to financial controversies which helped tumble the Executive earlier this year, including the Cash for Ash scandal linked to Ms Foster, Mr Kearney said they continue to overshadow the region.
"That is why Sinn Féin stood the DUP leader down from her position last January," he said.
"The focus on her future role in an Executive is completely misdirected and premature.
"That discussion will only arise when there is an acceptable implementation plan to restore public confidence in the political process and ensures that the institutions will work on the basis of proper powersharing, equality, respect and integrity."
On Friday, Ms Foster signalled her optimism that a deal to restore powersharing by a June 29 deadline could be done, adding that it "takes two to tango and we're ready to dance".
But Mr Kearney, speaking at an annual commemoration of Wolfe Tone, said: "It is not a game, and it is certainly not a dance."
He added: "If the DUP imagines it can wind back the clock, with a Tory side deal or not, and re-establish the institutions without adherence to equality and rights, then the DUP is indeed living in a fool's paradise."
Mr Kearney said his party's equality and rights agenda "is not negotiable".
"Continued refusal by the DUP and British government to accept these fundamental positions will create only one outcome: a future of permanent political instability," he said.
Northern Ireland has been without a powersharing executive since March and without a first and deputy first minister since January, after Sinn Féin collapsed the administration amid faltering trust and relations with the DUP.
Talks to restore confidence took a back seat in recent days as the political focus largely shifted to London and the DUP's deal to prop up the Conservatives at Westminster.
Parties return to talks on Monday in a last-ditch bid to break the impasse.
SDLP leader Colum Eastwood said two weeks is more than enough time to do a deal.
"The public will have every right to be unforgiving if another deadline is missed," he said.
"Weekend reports regarding the precarious position of the British Prime Minister must not stall or delay getting the institutions back up and running.
"The SDLP is determined to re-establish institutions in the North which last for the long term regardless of whether the Theresa May-led Government falls."