DUP leader Arlene Foster has warned Sinn Féin that the restoration of devolution is "no game".
The Democratic Unionist leader blamed Sinn Féin for the continued lack of self-government in Northern Ireland more than two years after the powersharing institutions collapsed in January 2017.
Mrs Foster made the comment while speaking to her party's Spring conference in Omagh.
It came less than 24 hours after the five local parties met with the British and Irish governments to discuss the resumption of political talks to revive Stormont.
There has not been a functioning devolved government in Northern Ireland since January 2017 following a breakdown in relations between the DUP and Sinn Féin over a botched green energy scheme.
The wrangle over the renewable heat incentive (RHI) was soon overtaken by disputes over the Irish language, the region's ban on same-sex marriage and the toxic legacy of the Troubles.
Numerous attempts at talks to resolve the impasse have been unsuccessful.
The two governments are expected to produce proposals to restart the talks process.
Mrs Foster today accused Sinn Féin of engaging in the "politics of ransom".
"Two years ago Sinn Féin walked out of the Northern Ireland Executive. After the subsequent election in March 2017, Sinn Féin refused to enter the Executive or the Assembly until their shopping list of demands was ticked off," she said.
She described it as the "politics of ransom" and also "careless" pointing to how major decisions have been left to senior civil servants.
She added: "The restoration of Stormont should not be about political brinkmanship or about party advantage. It should be about people.
"Whether it is contracts not being awarded, reforms not being implemented or new laws not being passed - be in no doubt our constituents are feeling the pain. It cannot go on.
"Four of the five parties in Northern Ireland are ready to move on and restore the Assembly.
"One party stands as the blockage.
"I warn Sinn Féin today from this platform: this is no game."
"Whatever your demands about the Irish language, they do not trump the genuine and heartfelt demands of the good people up and down this country."
Mrs Foster also made reference to the RHI scandal which has seen her party face questions and criticism over the role of its ministers and special advisers.
The RHI scheme was set up in 2012 to boost uptake of eco-friendly heat systems, but huge subsidies left NI taxpayers with a £490 million bill.
An inquiry set up to examine what went wrong completed its public hearings last year, and is yet to publish its findings.
Mrs Foster said in the RHI Inquiry hearings, there were "lessons for us all".
Responding to the DUP leader’s comments, Sinn Féin’s leader in Northern Ireland Michelle O’Neill said her party wants to see the removal of the major obstacles to restoring the political institutions, an end to the denial of rights and the full implementation of the Good Friday and subsequent agreements.
She added: "The people deserve good government which has integrity and an end to the DUP’s financial scandals. It is shameful that the DUP leadership continues to set its face against achieving this.
"Sinn Féin has made clear the issues which need to be resolved are not going away.
"We want an Assembly which operates differently from what has gone before, to usher in a new kind of politics, which is progressive, respectful, and has integrity."