Ireland should move to "Plan B" in the event of the programme for government being rejected, Sinn Féin leader Mary Lou McDonald says.
However, Ms McDonald said that a second general election of 2020 "would not be a "catastrophe".
Speaking to Ivan Yates on Newstalk FM, Ms McDonald said that she would look to form a government if either Fine Gael, Fianna Fáil or the Green Party rejects the programme.
"What needs to happen on Saturday. If that's the case, is that we need to move to plan B. And in all fairness Plan B really ought to have been Plan A, because Fine Gael and Fianna Fáil back in business together again is not the change people voted for in February."
Ms McDonald said that Sinn Féin and "the other parties of change" would form the "spine or core" of a new government, a programme for which could be turned around in "a fairly short process".
Ms McDonald accepted that the Dáil numbers were "tricky".
"But the fly in the ointment in this entire process has been the decision of by Fianna Fáil and Fine Gael to come together and to say categorically, pandemic or no pandemic, 'we're not talking to Sinn Féin', saying categorically to say we're coming together with the express intention of frustrating or slowing down or stopping the change that people have voted for."
Ms McDonald said that the grassroots of the Greens and Fianna Fáil had a choice between "putting Fine Gael back into power" or "speaking to Sinn Féin in a mature, democratic way".
Ms McDonald said that the plan hinged on Fianna Fáil "dropping their notion of stopping change", accepting that the current numbers would make it impossible to pass a budget.
If the programme for government is rejected, however, Ms McDonald said that she had no fear of a second election.
"We are in the grip of a public health emergency and I think that's bound to shape your view or your attitude towards a future election in the very near future, but I certainly wouldn't regard another election as a catastrophe, or a crisis. In a democracy I'd never regard an election as a crisis.
"If it's an election, Sinn Féin will grow and we will contest the election We run more candidate and we will go and we will again say to people who will know that Fine Gael and Fianna Fáil aren't the change that they want to give us a mandate."
Ms McDonald hinted that she would prefer Fianna Fáil to join her proposed government but that it would be "the parties of change in a very strong group, led by Sinn Féin".
She said that she had expressed admiration for Taoiseach Leo Varadkar's intelligence and abilities, but said that he had "awful, Tory politics".