Arlene Foster and Michelle O'Neill have publicly clashed over Sinn Fein's refusal to support the Democratic Unionist Party leader in an executive office after the Stormont election.
Going head-to-head for the first time in a pre-election debate the Sinn Fein and DUP leaders argued over power sharing arrangements should they both be returned in March as the two main parties.
Mrs O'Neill insisted yet again she was not prepared to go into government with Mrs Foster until a public inquiry into the botched Renewable Heat Incentive (RHI) scheme had concluded.
She said DUP "arrogance, contempt and serious allegations of corruption around the RHI scandal" had forced next month's snap election.
However, Mrs Foster hit back that it was not up to Sinn Fein to decide who should lead her party.
She also said that this election was "an attempt by Gerry Adams to push forward his radical agenda."
As tensions continue to simmer between the DUP and Sinn Fein, the two party leaders aired their differences face-to-face during the UTV Election Debate involving the region's five largest parties, DUP, Sinn Fein, SDLP, UUP and Alliance.
"We can go into government (after the election), but we couldn't go into government or support Arlene Foster in the position of first or deputy first minister while an inquiry is ongoing.
"The public need answers and deserve answers," said Mrs O'Neill.
Mrs Foster responded: "It's not a matter for Michelle O'Neill or Gerry Adams or anyone else in Sinn Fein to say who should lead the party."
Mrs O'Neill hit back: "Its not for me to say who will lead the DUP, but it's Sinn Fein's right to say who they will go into government with."