The NSW premier will not remove Tim Crakanthorp from the Labor party room despite the state's corruption watchdog launching an investigation into the ousted minister.
Premier Chris Minns referred the Newcastle MP to the Independent Commission Against Corruption (ICAC) last month after it was revealed he did not disclose family holdings in Broadmeadow while minister for the broader Hunter region.
Documents provided to the NSW parliament reveal ICAC chief commissioner John Hatzistergos confirmed the anti-corruption body was conducting a "preliminary investigation" into whether Mr Crakanthorp breached the ministerial code of conduct.
But Mr Minns on Thursday said he would wait until ICAC launched a formal investigation - including a public inquiry - before making a decision on the MP's party future.
"If they move to the next stage, obviously I'll take action," he told reporters.
"Given it's a preliminary inquiry, I don't know ... what the shape or nature of that potential inquiry will be and I think it's appropriate that we wait and see."
Mr Minns denied he was continuing to support Mr Crakanthorp because of his government's minority grip on power.
"We've been in power for six months, I'm not aware of any vote that's come down to one - we've had good support from the crossbench," he said.
Mr Crakanthorp was forced to resign from his portfolio after disclosing that his wife and her family had substantial property interests in Broadmeadow, which is home to major stadiums and is on the proposed route for the Newcastle light-rail extension.
While his regional portfolio had no executive powers, Mr Crakanthorp was responsible for lobbying and co-ordinating other ministers to drive development in the Hunter.
The Newcastle MP, who remains on the back bench, also served as minister for skills, TAFE and tertiary education until he was removed from the role.
Mr Crakanthorp said he self-reported the breach after becoming aware of his in-laws' holdings and the potential conflict of interest.
Mr Minns previously described the earlier non-disclosure as a significant breach of the ministerial code.
Both the ICAC and the state's Cabinet Office have refused to release further documents to the parliament's upper house, claiming their disclosure could prejudice the corruption probe.
Those documents include briefings prepared for Mr Minns, as well as disclosures made and information sought by Mr Crakanthorp in relation to the ministerial code.