A poll for the independent think tank Policy Exchange showed 56% of those questioned were opposed to any merger.

It comes just weeks after a Mori survey revealed 58% of people questioned wanted a referendum on the issue.

The Northumbria and Durham forces are in favour of the government-backed merger. Cleveland is resisting the move and has threatened legal action.

In the latest poll, carried out by Populus for Policy Exchange, 359 people were questioned.

'Less accountability'

The results showed 56% opposed the plan to merge the three forces, with only 36% in favour.

James O'Shaughnessy, head of research at Policy Exchange, said: "The results of our poll are unequivocal. The government's proposed merger between Cleveland, Durham and Northumbria police forces is unpopular with local people.

"Nationally, the Association of Chief Police Officers is already making contingency plans to cut 25,000 police officers posts to offset the �600m cost of restructuring.

"Residents in the North East know that merging police forces will mean fewer police, less accountability and less attention paid to local crime. Home Secretary John Reid must act to stop these plans now."

The Northumbria and Durham chief constables disputed the impartiality of the Mori survey of more than 4,000 people, which was paid for by the Cleveland force.

The latest survey followed a report by Policy Exchange on police force restructuring called Size Isn't Everything: Restructuring Policing in England and Wales. It argued that planned mergers would prove unpopular and unworkable.