Sinn Féin say they are "ready to lift the phone" to other parties if the Programme for Government is rejected on Friday.
As concern continues to rise that the historic deal between Fine Gael, Fianna Fáil and the Green Party might not make it over the line due to a two-thirds majority required from a split Green Party membership, Sinn Féin say they stand ready on the sidelines to enter the fray.
"We've made it clear, if this deal doesn't go through, if the membership of any of the parties reject it, then we will be lifting the phone, in the first instance those with a mandate for change," Sinn Féin's Finance Spokesman Pearse Doherty said.
"We will engage with all parties, and it's up to others to respond."
Sinn Féin have not ruled out speaking to any party but have previously said that Fianna Fáil and Fine Gael do not "represent change", they say their first port of call will be left parties such as Labour, Social Democrats, People Before Profit and the Green Party.
Mr Doherty said his party would consider a confidence and supply arrangement with others, including Fianna Fáil, whose leader Micheál Martin did not reject speaking to Sinn Féin in an interview on Tuesday morning in the instance of a 'No' vote this week.
"We could come to an agreement to present to others," he said.
"It's up to them, whether they want to play the old style of politics, to ignore the fact that Sinn Féin had over half a million people vote for our party and not talk to us, or they can change their tune.
"Let's remember we're in this situation because Fianna Fáil and Fine Gael have decided to exclude our voters and not even engage in talks on government formation.
"I think it important we have a change led government, led by the left.
"On Friday, if this deal doesn't go through, we'll engage first and foremost with those with a mandate for change and reach out to others through confidence and supply or whatever, but that requires engagement and talks and we've always said we're willing to talk to all parties."
Mr Doherty is confident a deal could be done quickly as the parties Sinn Féin are interested in leading with, have already met for negotiations.
"This could be done quickly, the numbers are challenging when parties decide to exclude the largest political party, that makes it all the more challenging.
"There's a lot of common ground, we've had very good engagement in the past and if the opportunity arises we would want to be involved in short, sharp talks to get government formed, but this isn't solely in the hands of Sinn Féin."