The botched Renewable Heat Incentive (RHI) scheme remained the hot topic as NI party leaders again clashed over the issue in the second TV election debate.
Sinn Féin's Michelle O'Neill said she would not go back into government with DUP leader Arlene Foster while there was a RHI "cloud hanging over her".
Mrs Foster said there was not a "scintilla of evidence" to support corruption allegations over the scheme.
Leaders were also put on the spot over to whom they would transfer votes.
Mrs Foster criticised Ulster Unionist leader Mike Nesbitt for saying during the campaign that he would transfer his second preference vote to Colum Eastwood's SDLP.
"No serious commentator is saying that with a vote for Mike, you'd get Colum," Mrs Foster said.
"If you vote for Mike, you will get Michelle, that's the reality."
Mr Nesbitt replied: "People voted for you the last time and they got Martin McGuinness, and he wrote your resignation letter."
Mrs Foster lost her job as first minister in January after Mr McGuinness resigned as deputy first minster in protest over the DUP's handling of the RHI scandal.
The second TV debate of the election campaign, hosted by BBC Northern Ireland, featured the leaders of the five biggest parties at Stormont - the Democratic Unionist Party (DUP), Sinn Féin, Ulster Unionist Party (UUP), Social Democratic and Labour Party (SDLP) and Alliance.
Mr Eastwood said Mr Nesbitt was "very brave" to say he would give his second preference vote to the SDLP and added the public were "way ahead" of politicians on cross-community voting.
"I'm an Irish nationalist, Mike Nesbitt's an Ulster Unionist, I won't be any less of an Irish nationalist if I transfer across community. It doesn't affect one iota my nationalism. I think it's the kind of politics that we need to be embracing."
'Holding their nose'
Alliance leader Naomi Long said her party had "fought every election" on the basis of seeking cross-community support.
"I am glad that other parties are talking about actually co-operating on the basis of doing so voluntarily rather than doing it, as others have said, holding their nose to go into government with each other," she said.
Mrs Long added that people are tired of being "pulled back into the ditches" and wanted to move forward.
The snap election was called after a coalition led by the DUP and Sinn Féin collapsed over the handling of the RHI scheme.
'Whiff of corruption'
Former first minister Arlene Foster set up the scheme in 2012 when she was enterprise minister; it was an attempt by the Northern Ireland Executive to increase the creation of heat from renewable sources.
But flaws in setting the scheme's subsidy rate left it open to abuse as claimants could earn more cash the more fuel they burned; the lack of cost controls led to an overspend that could cost taxpayers £490m over the next 20 years.
Sinn Féin's leader north of the border, Michelle O'Neill, said: "I cannot go into government with Arlene Foster, in the position of first or deputy first minister, whilst there is a cloud hanging over her.
"The full [RHI] investigation needs to report, but the public will have their say."
Asked if she would respect her mandate if voters support Mrs Foster, Mrs O'Neill told the debate she could not dictate who leads the DUP, but could dictate who Sinn Féin enters government with and said the DUP "will have a choice to make" after the election.
Earlier in the debate, Mrs Foster said there was not a "scintilla of evidence" in relation to RHI allegations made against her.
"Would it not have been more intelligent, would it not have been better to have had the public inquiry first and then had the election? Because then we would have had the full facts for everybody to make a judgement," she said.
The DUP leader has repeatedly warned during the campaign of what she calls Sinn Féin's radical Republican agenda, and she used that phrase again several times during the debate.
The UUP leader, who has proposed an alternative coalition with the the SDLP, said the DUP and Sinn Féin "only share space, power and responsibility because the law says they have to".
Mr Nesbitt urged people to vote for change, saying: "We need an end to 10 years of government hallmarked by incompetence, arrogance, cronyism and the strong whiff of corruption."
Speaking on BBC Newsline Ireland after the debate, leaders of Stormont's smaller parties were scathing about the performances of their larger rivals.
Traditional Unionist Voice (TUV) leader Jim Allister said: "I think the audience saw that there is no prospect of those five parties providing durable, workable good government."
He added: "If you vote for these five main parties, you get more of the same - the very thing that isn't working."
Mr Allister said Stormont would never work while it operated under a system that "insists" on holding Sinn Féin at the heart of government.
Green Party leader Steven Agnew said the debate was a "wasted" chance for the five main parties.
"They've wasted the last 10 years in government between them and they've wasted the opportunity to stabilise politics in Northern Ireland."
He said the Green Party was the "first to raise problems" with the RHI scheme and was "still the only party to propose a workable solution".
'Take a kicking'
People Before Profit's Fiona Ferguson said: "Not once tonight did we hear about the crippling austerity that has been bringing our community to its knees for the past 10 years.
"We also didn't hear about any sort of solution to the housing crisis nor the healthcare crisis that faces most people in this country."
She said People Before Profit had heard a lot of anger from voters while canvassing and believed that the big parties will "take a kicking in this election".
The latest TV debate was held ahead of polling day on 2 March.