Some crimes in Warwickshire may not be investigated if cuts are too severe, the police federation has warned.
The Home Office will learn how much of its annual £10.2bn budget will be cut when the government's Spending Review is announced on Wednesday.
Pc Simon Payne, from Warwickshire Police Federation, said any cuts would go "into the bone" of the force.
The force has already outlined plans to save cash, including closing stations to the public late at night.
Pc Payne said the Warwickshire force could not take any more significant cuts without front-line services being affected.
"We are not talking about efficiency savings, we are talking about cuts," he said.
"So I can see, if the savings are not reasonable, issues like certain crimes no longer being investigated.
"Police stations will be closed and the level of police presence on our streets will be visibly reduced."
Warwickshire Police is having to make multi-million pound savings ahead of the government cuts.
The government is planning big cuts to spending to reduce the budget deficit and allow it to start paying back its debts.
In the 2009-10 financial year, the budget deficit hit a record £155bn.