GREEN Party leader Steven Agnew has said restoring Stormont must include a review of how to uphold the ministerial code in light of RHI revelations.
Senior civil servant Andrew McCormick on Thursday told the RHI inquiry that breaches of the ministerial code "happened time and again", but it was "almost impossible to enforce".
He also said executive parties' fear of leaks led to a "culture of very limited record-keeping", and an attitude developed that "if you write something down it'll probably appear in the newspapers".
Inquiry chair Sir Patrick Coghlin expressed surprise, saying that Stormont rules were "completely ignored".
"There cannot be, from a public point of view, a positive perception of the political process if that occurs," he said.
Northern Ireland has not had a power-sharing government since the DUP and Sinn Féin-led executive collapsed early last year.
Mr Agnew, an MLA for North Down, said ministerial accountability must be at the centre of any restoration of Stormont.
"I first called on the executive to promote accountability and transparency through an independent process to investigate alleged breaches of the ministerial code of conduct back in 2015," he said.
"Three years later, the RHI inquiry is unearthing evidence of the grubby conduct of executive ministers, our devolved institutions are gathering dust and public trust in politics is at a serious low.
"Any return to devolution must be accompanied by a genuine means by which alleged ministerial wrongdoing can be properly investigated and dealt with."
