Tories complain that ministers do not provide enough jail spaces
The Ministry of Justice is investigating claims that new bail hostels have opened without local residents being consulted.
The locations of 150 hostels across the UK, run by private company Clearsprings, have been obtained by Channel Four News.
It says councils are not consulted before they open and that low-risk offenders are left unsupervised.
Officials say Clearsprings is under a contractual obligation to consult.
The hostels house suspects awaiting trial and offenders released before the end of their sentences.
Unlike public sector hostels run by the Probation Service, the hostels are not staffed 24 hours a day.
Clearsprings states on its company website that this is not necessary for offenders who are placed in their hostels.
Instead, they receive regular planned visits from staff.
Sites for the hostels include Peterborough, Bridgend, Durham and Plymouth.
Shadow justice secretary Nick Herbert said: "It's wrong to house prisoners in residential areas simply because the government has failed to provide enough jail spaces, but doubly wrong that local people are never consulted beforehand.
"Placing offenders in housing where they receive almost no supervision or support is no way to provide effective rehabilitation and places the public at unnecessary risk."
Prisons Minister David Hanson said he expected 400 people to enter the scheme by June, half of them awaiting trial.
"The courts judge them as a safe risk to put in the community and I feel the system helps people."
The Ministry of Justice said Clearsprings is under a contractual obligation to consult where it plans to open bail accommodation.
"Any reports that it has failed to do so will be investigated," a spokesman said.
"Those in Clearsprings accommodation are innocent until proven guilty. Defendants who pose a risk to the public will continue to be held on remand."