Police and crime commissioners could cost more than £130 million to set up and run in the first year, new figures show.
Holders of the controversial new posts will also be the focus of a dramatic shift in power from Whitehall in a move that will usher in a new era of policing, Home Secretary Theresa May said.
But shadow home secretary Ed Balls warned the move stood in the face of a 150-year tradition of keeping politics out of policing and would come only as a result of unnecessary expense in the face of 20% cuts to police budgets.
Police authorities, which will be scrapped under the plans, said it was the "wrong policy at the wrong time".
But Mrs May insisted the most radical reforms to policing in more than 50 years would "give people value for money".
Asked about the lack of the Home Secretary's power to intervene if a commissioner or force was failing, Mrs May said it was time for change and the locally-elected commissioners would have a "mandate from the people in relation to that police force".
"The accountability will be directly to that police and crime commissioner," she said.
"This is an era where not all the decisions come from the centre.
"It isn't that Whitehall is the power that is telling everybody else what to do.
"We're having a bold, dramatic shift of power. This is a Government that believes in shifting power from the central to the local level."