Up to 450 jobs could go at Warwickshire Police, a spokesman has said.
Deputy Chief Constable Andy Parker said an early review of the force's finances indicated it needed to reduce its budget by £22m over four years, instead of an estimated £13.4m.
Proposals to address the funding gap will be given to the police authority over the next months, he said.
He was reacting to the government's announcement which gave details of a series of funding cuts to councils.
"While it is not possible to provide a definitive figure on future workforce levels, as we still have more work to complete our our buildings, fleet, IT and other non-staff costs, we do know that our workforce will need to reduce in size by around 450 people during the next four years," he said.
"We will be doing everything we can to minimise the number of people we lose."