A government department whose chief executive is accused of assaulting a woman on her staff is overseeing an investigation into the incident itself.
The Public Service Association (PSA) says it is concerned the woman might not have her case properly examined.
The woman was working for the Department of Building and Housing when it is alleged she was verbally abused and physically assaulted by her chief executive, Katrina Bach.
The department commissioned a investigation by a lawyer. It will not discuss the case for fear of prejudicing the outcome.
The PSA says an investigation of a chief executive should not be commissioned by the executive's own department, but by the State Services Commission, to maintain transparency.
Veteran public servant and public sector watchdog Len Cook agrees the commission would be the proper investigator.
Mr Cook, the president of the Institute of Public Administration, says that would benefit the person being criticised and the person who has to defend the public service generally.
The State Services Commission is not commenting until the process is over, but does say an organisation being complained about is normally the one to establish an investigation.
It says the commissioner will see the report when it is finished.
Employment law specialist Max Whitehead says the department may be taking a risk by leaving its chief executive in her role while the claims are investigated.
Mr Whitehead, the head of human resources firm The Whitehead Group, says any employment investigations involving government departments are usually extremely rigorous.