A WA parliamentary committee will investigate Barry Urban after he admitted wearing a service medal he was not entitled to and lied about a diploma, but failed to answer other questions about his military service and education.
Mr Urban, who has quit Labor but remains the independent member for Darling Range, told parliament on Thursday he falsely claimed to have a diploma in local government, revealing the final module was not completed.
He said he had now amended his resume and was seeking to substantiate other tertiary qualifications.
There are allegations two UK universities he declared to have attended have no record of him.
Mr Urban also failed to clarify his claims about investigating war crimes in Bosnia.
He said he was proud to have served with the British army from 1985 to 1989, and was deployed to Cyprus with the United Nations peacekeeping force from 1988 to 1989.
Mr Urban said he was also proud of his service with British police from 1989 to 1998 and WA Police from 2005 to 2012.
"In relation to other allegations made with respect to my service history, I am currently seeking further information from the relevant authorities to substantiate that service history."
The embattled MP also addressed his medal scandal, saying he ordered a commemorative international police service medal but received an Australian Police Overseas Service Medal, and meant no offence.
"When I was first asked about the medal by the media and the premier, I was under the genuine but mistaken belief that it was the correct medal," he said.
"I am embarrassed by my error and for the hurt I may have caused."
Mr Urban also revealed he suffers from post traumatic stress disorder and was continuing to seek professional treatment.
"Like many service personnel, I have seen and experienced things that are very hard to fathom," he said.
"In times of high stress, my PTSD symptoms can make it hard for me to function."
Mr Urban left parliament immediately after his speech.
Premier Mark McGowan said Mr Urban's explanation was not comprehensive enough, and a motion was passed for the procedure and privileges committee to investigate parliamentary statements he made.
The opposition had tried to amend the referral to include whether Mr Urban was a fit and proper person to serve in parliament but it was rejected.
The Liberals also wrote to the Speaker with their request, but it too was knocked back.
"(We need) a wholesale inquiry into Mr Urban's bona fides and the premier's handling of the matter," Opposition Leader Mike Nahan said in a statement.
"(Labor is) managing Mr Urban to minimise political damage rather than to maximise transparency, accountability and to seriously interrogate Mr Urban's fitness for office."
Dr Nahan told parliament Mr Urban could have made a statement weeks ago but left it to the last sitting day of the year to avoid scrutiny.
Police Minister Michelle Roberts said an investigation into Mr Urban's police application did not identify any criminality.
Mr Urban was elected in March, defeating former Liberal minister Tony Simpson.
Australian readers seeking support and information about depression can contact Lifeline on 13 11 14.