Internal documents obtained by 1233 ABC Newcastle, via freedom of information laws, reveal the NSW Office of Sport, which operated the centre, went against the advice of its own experts when it suddenly closed the facility in March.

NSW Office of Sport cited fears a coal ash dam wall at Eraring power station could fail in the event of a major earthquake - deemed as a once-in-a-5000-year event.

Assistant secretary of the Public Service Association, Troy Wright, said on Wednesday that it appeared the closure decision might need to be referred to ICAC.

"What this looks like is the government, while in caretaker mode, was in cahoots with a private energy company to manufacture an excuse to close the centre and in doing so advance their commercial interest in expanding the ash dam," he said.

"We are anxiously waiting for the outcome of the Dam Safety Committee report to ascertain if there actually is a risk, but this is shaping as something far more serious, and referrable to ICAC."

According to the ABC report, NSW Dams Safety Committe head Chris Salkovic and NSW Public Works chief emergency engineer Martin Dwyer did not agree with the closure.

Lake Macquarie MP Greg Piper described the revelation on Wednesday as "extraordinary, but not surprising".

"The Office of Sport was not supported by the bosses of the NSW Dam Safety Committee or NSW Public Works when it sought advice on closing Myuna Bay," Mr Piper said.

"One warned against exaggerating the risk posed by Origin's ash dam wall, the other suggesting that Origin was seeking to further its own interests...

"It begs the question as to what went on besides what we have now found out, and just what role Origin Energy played in seeking this closure."

An Origin Energy spokesman said the company strongly denied it influenced the closure of the facility.

"Origin strongly refutes the allegation contained in the emails obtained by the ABC," he said.

"We have provided the engineering assessments of the ash dam to Mr Greg Piper MP, Lake Macquarie City Council, the Office of Sport, the NSW Roads and Maritime Service, NSW minister for sports and NSW shadow mnister for sports, while the Dams Safety Committee are currently undertaking an independent peer review of these assessments on behalf of the NSW government."

In a media release issued on March 29, Origin said it had contacted the NSW Office of Sport to discuss an engineering review of the Eraring ash dam.

"On our advice, the Office of Sport has agreed to close the centre to ensure the safety of clients and staff," it reads.

Origin executive general manager, energy supply and operations, Greg Jarvis said in March while he understood the likelihood of a serious seismic event was low, and that a breach of the dam was therefore very unlikely, the company was taking the "only responsible measure by acting on the worst-case scenario".

"We understand the significance of the centre to the local community and acknowledge the inconvenience that this closure causes," he said.

"We would like to thank the NSW Office of Sport for acting expediently on our advice."