The NSW gaming regulator is investigating ASX-listed Star after media reports claiming the company enabled suspected money laundering, organised crime, fraud and foreign interference at its venues, including The Star Sydney.

Mr O'Neill was due to appear on Monday, but the hearing was adjourned until Tuesday and later pushed back until May 23, with a NSW Department of Enterprise Investment and Trade spokesperson saying the probe was "delayed".

They declined to say why the delay had occurred.

Hearings would resume next week with evidence from Star director Richard Sheppard and Mr O'Neill followed by closing submissions from counsel assisting the review, the spokesperson told AAP.

Damning evidence at the inquiry has so far prompted the resignations of the gambling giant's chief executive Matt Bekier, chief financial officer Harry Theodore, chief casino officer Greg Hawkins, and chief legal and risk officer Paula Martin.

Many of Star's directors are also expected to step down after testimony of mismanagement, making way for renewal at the embattled company.

Directors Sally Pitkin and Gerard Bradley have already announced their intention to step down from the board.

Mr O'Neill, former boss of Australian Rugby Union, was appointed as the casino's interim executive chairman last month after Mr Bekier's resignation.

Mr O'Neill, who was already chairman, is the last witness on the probe's hearing schedule that has worked its way through the casino's top brass from mid-March.

The inquiry was adjourned on Friday after Ms Pitkin choked back tears when asked what she thought went wrong at the gambling company, saying there had been indifference about money laundering.

"That indifference has come about because of a failure to understand the harm that occurs from money laundering," she said.

Australian Associated Press