More than two-thirds of people in Northern Ireland want policing powers devolved to Stormont, according to a poll commissioned by the Northern Ireland Office.
Members of the Stormont Assembly will vote on the issue tomorrow.
US Secretary of State Hillary Clinton was in contact with Ulster Unionist leader Reg Empey over the weekend after his party announced it would not be supporting the proposals.
The UUP executive met tonight to discuss the situation.
Mr Empey said his party will not be blackmailed or bullied by anybody over its attitude to devolution.
He was responding to comments from Martin McGuinness at the Sinn Féin Ard Fheis over the weekend.
On RTÉ Radio's Morning Ireland, Northern Secretary Shaun Woodward said the UUP had not been sidelined during the negotiations, which led to the Hillsborough deal.
He said it was vital the party listened to their supporters.
Alliance Party leader David Ford said the Ulster Unionist opposition was almost irrelevant because the public mood was such that the devolution plan will go ahead anyway.
Sinn Féin's Gerry Kelly has said the UUP is making a huge political mistake by opposing the devolution plans.
