Mark McGowan says he is "very disappointed" in Labor MP Barry Urban for wearing an Australian Police Overseas Service Medal to which he was not entitled.

But the WA Premier says he has no reason to doubt Mr Urban's CV, including serving for the WA Police and the British police and military. His service also involved peacekeeping operations in Bosnia in the 1990s.

Barry Urban (right) with Mark McGowan on the campaign trail. Credit:Facebook / Barry Urban

Mr McGowan said on Tuesday he had directly asked Mr Urban about his military and police record.

"He was wearing a medal to which he was strictly not entitled and I expressed my disappointment about that," Mr McGowan told Radio 6PR.