Sinn Fein leader Gerry Adams has described Arlene Foster as a "backwards person" as he said the Stormont crisis is not an "orange and green issue".
Stormont's institutions collapsed on Monday as Sinn Fein confirmed it will not nominate a deputy First Minister meaning a snap election in late February or early March is on the cards.
It comes as Martin McGuinness resigned from the post last Monday over the DUP's handling of the Renewable Heating Incentive scandal.
Speaking to RTE's Today Show with Sean O'Rourke Mr Adams said the impasse was "not an orange and green issue".
He said: "We are the party of dialogue, but there has to be a basis for such talks. Martin and I were agreed, you can only be involved in those sorts of talks if there was a reasonable possibility that they would succeed.
"When governments fall out and there is very good reason for this government to fall out, then we move into elections."
He added: "This isn't an orange and green issue. Unionists people are as outraged at the possibility that half a billion pounds of their money gone astray as anybody else.
"That has to be sorted in the first instance.
"And then the issues that we are all familiar with, the rights of Irish speakers, the rights of minorities, the bill of rights - all of that has to be dealt with.
Mr Adams said the RHI scandal was the "tipping point" but that all these issues must be dealt with.
He said: "The DUP are bound to know, that the lack of even good manners the lack of respect, the way they deal with issues are all elements which brought us to this point.
"The big reason for the tipping point was the RHI scandal and how they dealt with it.
"I would like to think they would be sorted out or Arlene Foster will never be First Minister ever again."
Mr Adams slammed Mrs Foster as "backwards" as he spoke on the issue of equality which in November 2014 he said was the Trojan horse of the entire republican strategy to "break these b*****ds".
He said: "Because she has not in the period that she was in that post, picked up on the example se,t despite all the difficulties, of her two predecessors.
"Martin McGuinness and whatever anybody thinks of Sinn Fein, everybody knows Martin broke his back to try and make this work.
"On a personal level I think Arlene is very good and well mannered and well humoured.
"But she is not the leader of Unionism, she is the leader in the office of first and deputy First Minister, a co-equal office of all the people of the north."
When asked if Sinn Fein had "walked off the pitch" during the crisis - Mr Adams denied this saying that Mr McGuinness, who has suffered ill health, was travelling to Stormont for proceedings from his sick bed.
"No we haven't. We haven't walked off the pitch at all," Mr Adams said.
He added: "Martin McGuinness is travelling from his sickbed to Stormont this morning to be part of whatever emerges in the course of the day's business there.
"I'm making my way to Dublin now. Our Oirechtas team is meeting before the Dáil resumes tomorrow morning.
"So far from walking off the pitch, Sinn Fein is playing right across the pitch and we're playing on behalf of the people on our opponent's side of the field."