Police and crime commissioners could cost more than £130 million to set up and run in the first year, figures showed today.
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.
"People will have the ability to remove a police and crime commissioner come election time."
But she said it was not the case that there would be no action in the four years between each election.
"If a force was completely failing, there would be questions being asked, there would be police and crime panels, I expect HMIC (Her Majesty's Inspectorate of Constabulary) would be looking at this as well.
"But I think what's important is to get away from the concept that it is always the case that it's going to be central Government that takes decisions on these things.
"That's the change. There is a complete shift in power and thinking."
The Home Secretary will have no powers to sack a commissioner - or a chief constable - under the proposals.
But she could intervene "if the police and crime commissioner was preparing to set a budget that was less than necessary to maintain appropriate policing in the area", Mrs May said.
The Home Secretary will also have the power to ensure "proper collaboration" on national policing issues.
Mrs May added the new system "will cost no more than police authorities".
But the elections, to be held every four years from May 2012, will cost £50 million and there will also be a one-off transition cost of £5 million, an impact assessment released by the Home Office showed.
Mrs May said: "I do think it will give people value for money.
"I think this is a very important step which is going to ensure that policing responds to local needs.
"I think that direct accountability for a police and crime commissioner will be a very important step-change."
Each of the new roles could attract pay and benefits of about £122,000, the impact assessment showed, but the exact amount will be set following consultation with the senior salaries review body.
Mrs May said the Government was not setting a level for the minimum turnout needed to ensure those elected had a mandate.
"My strong belief is that there's a lot of people out there who think it's absolutely right to have the ability to elect somebody who is going to have responsibility for policing in their area," she said.
Policing and Criminal Justice Minister Nick Herbert said it should be up to the public to decide who they want to stand for the new roles.
But serving officers, staff at the Serious Organised Crime Agency, the Independent Police Complaints Commission, the National Policing Improvement Agency and councils - excluding teachers - will all be banned from standing.
Commissioners will be suspended if charged with an offence carrying a maximum sentence of two years or more and disqualified from standing if convicted and sentenced to three months or longer - even if that sentence is suspended.
And the commissioners will not be able to serve more than two terms, each of four years.
Mr Herbert added the Government was also carefully considering MPs' suggestions that there should be a four-year cooling-off period for former senior officers before they can take up the posts in their force area to avoid any conflicts of interest.