The government is being urged by one of its MPs to rethink plans to merge Lancashire and Cumbria Police.
The Home Office wants to reorganise policing in the UK
The merger was agreed as part of the massive reorganisation of UK police forces, which the Home Office says will improve efficiency.
But Gordon Prentice, the Labour MP for Pendle, in Lancashire, said senior officers would lose their jobs.
Home Office Minister Joan Ryan said there was support for the merger within the North West.
Both the Cumbria and Lancashire police authorities have agreed to the new force, called the Cumbria and Lancashire Constabulary.
But Mr Prentice raised his concerns about the future of some senior police officers in the Commons on Monday.
He said: "People who are, presumably, at the height of their powers are going to be pensioned off.
"Isn't it the case that this reorganisation - like every other reorganisation - is going to cost an absolute arm and a leg and may not deliver the benefits we are told to expect?"
Mrs Ryan said: "Lancashire and Cumbria are very keen to see this merger go ahead.
"This can be an expensive process, however it is about creating the police forces that can provide the protection for our communities that they both want and deserve."
The Home Office wants to create larger "strategic" forces across England and Wales which it says will help police combat terrorism and organised crime and also enhance neighbourhood policing.