The Government could be billed for £1 million by police authorities in the West Midlands for merger plans which have now been abandoned.
Authorities are considering asking the Home Office to pay the costs of consultation, legal advice and employing staff to examine the proposals.
It follows an announcement by North Wales Police Authority that it is to send the Government a bill for £375,000.
A West Mercia Police spokeswoman said the force was considering whether to charge the Government £300,000 for the expense of taking part in the merger process, which it opposed.
Staffordshire Police Authority will discuss whether to demand repayment when it meets on Tuesday.
A spokesman for West Midlands Police said: "Police forces and police authorities are considering their options and no decision has been taken by West Midlands Police at this stage concerning possible recovery of costs incurred."
A spokeswoman for Warwickshire Police said: "We are considering whether to charge the Home Office."
Last night the Home Office said there was no guarantee it would agree to pay back any of the money which had been spent.
A spokeswoman said: "Police forces can put in additional funding requests to the Home Office at any time and we would always consider them." The merger project was the brainchild of former Home Secretary Charles Clarke but collapsed earlier this month after the only two forces to volunteer to merge withdrew, blaming the Government for failing to offer cash to finance the changeover.
Mr Clarke aimed to introduce the scheme to consolidate England and Wales's current 43 forces into something like 24 larger forces, saying they would be better prepared to fight terrorism and organised crime.
But it proved unpopular with the forces and the Cumbria and Lancashire constabularies were the only complete group to agree to merge.
However, following a meeting with Policing Minister Tony McNulty earlier this month, both police authorities withdrew their support after the Government failed to resolve a crucial issue of funding via increases in council tax precepts.