One of Britain's most senior police officers has told the BBC that plans to merge many of the forces across England and Wales are "verging on a shambles".
Some senior officers want a single national force
Dyfed-Powys Police Chief Constable Terry Grange said the plan was "Alice Through the Looking Glass stuff".
The government wants to merge the four Welsh forces into one unit.
Mr Grange supports the move in principle, but accused the Home Office of a lack of "financial, professional and political backing".
He believes a single force is the best option for Wales, but insists the huge cost of restructuring must be paid for by the government.
Ministers have told force leaders to borrow money to meet the merger costs, and Home Secretary Charles Clakre has offered extra money to police authorities which volunteer to merge their forces on 23 December.
But the Association of Police Authorities (APA) has accused Mr Clarke of trying to "bribe" forces into submission.
Earlier this month MPs on the Welsh Affairs select committee questioned the chief constables of the four Welsh forces - South Wales, Dyfed-Powys, Gwent and North Wales - and their police authorities about the planned changes.
It followed the restructuring proposals announced by Mr Clarke in November, which could see the number of forces in England and Wales could be reduced from 43 to 12.
When the Wales chief constables were questioned, the only one not supporting the plans was Richard Brunstrom of North Wales Police.
He agreed there was "a very great deal of logic" to a single force but questioned the flexibility of the proposals.
Chief Constable Richard Brunstrom has questioned the plans' flexibility
On Friday Mr Brunstrom told the BBC his biggest concern was "the rush".
APA chairman Bob Jones said on Friday no police authorities would agree to the plans unless Mr Clarke promised the government would meet all the merger costs.
"We will not be bullied or bribed into making decisions in three months about changes to our police forces which have done a good job for the last 30 years," he said.
The APA estimates the reorganisation would cost between £500m and £600m.
It said borrowing money to meet the costs would lead to less money available for local policing, because forces would have to pay interest.
It wants an assurance that council taxpayers would not have to "dig deeper into their pockets to pay for mergers".
Advocates of the changes say larger police forces work better and the plans could save up to £2.3bn over 10 years.
Failures that led to the murders of Holly Wells and Jessica Chapman in Soham, Cambridgeshire, exposed the police to criticism for poor communication between forces.
There are also concerns some forces are too small to deal with the threat of international terrorism.
But the Tories and Lib Dems argue the reorganisation will break the link between police and local communities.