The Patten Commission on Policing is inhibiting the RUC's effectiveness, according to the UUP's security spokesman, Mr Ken Maginnis.
At the publication of a party document on decommissioning yesterday he also claimed that the worsening security situation in Northern Ireland meant it may soon be necessary to recall British army troops.
The 20-page booklet, Disarmament - Pathway to Peace, outlines the UUP position on decommissioning and states that with the worsening security situation and rise in punishment attacks, the Patten Commission should consider suspending work until a "normal" society had been established.
Mr Maginnis said the RUC felt obliged to embark upon a public relations exercise for the commission and were reluctant to venture into "local areas where para militaries dominate" because of possible allegations of harassment.
He added it was unlikely the commission could make relevant proposals in this climate. "You cannot adjudicate for normality in the vacuum of abnormality."
But the UUP was not attempting to "destroy" the policing commission, he said. "We're drawing attention to the almost impossible task that they have in the current circumstances."
Responding to Mr Maginnis's comments the Northern Secretary, Dr Mo Mowlam, stressed that the commission was part of the Belfast Agreement.
"I'm not into un-picking that Agreement. It is still in the process of being implemented," she said.
The Sinn Fein Assembly member, Mr Gerry Kelly, said Mr Maginnis's statement represented an attempt to "rewrite and undermine" the agreement.
Outlining the reasoning for drawing up the document, Mr Maginnis said it was to reassure the unionist community that decommissioning was included in the Belfast Agreement and was "necessary".