Concerns were raised at the Scottish Police Federation (SPF) conference.
Police Scotland Chief Constable Iain Livingstone said action was being taken.
SPF officer holder David Threadgold told the conference at Turnberry in Ayrshire: “There are officers that are turning up at Tulliallan [Police College] wearing trousers that they have bought themselves because the uniform provided is of such poor quality.
“That will extend across the country.”
He asked Mr Livingstone if he was “embarrassed by the state of our police equipment and uniform”.
Mr Livingstone replied: “The uniform in terms of the quality of the trousers, the quality of the operational vests, they haven’t been as good they should have been.”
He said he had recently approved a change to issuing “higher quality cargo pants”.