Residential treatment centres should be opened for the most dangerous paedophiles, says the government.
Plans to house offenders draw anger in local communities
Each hostel would house about 25 high-risk offenders once freed from prison.
Previous attempts to open such centres have been thwarted by local opposition, but ministers say there is evidence they would reduce re-offending rates.
Paul Cavadino, chief executive of the charity Nacro, said the move would actually increase public safety because sex offenders would be better monitored.
The National Probation Service report said such centres could cut the numbers being reconvicted within two years from 30% to 10%.
The programmes, across England and Wales, would be aimed at men deemed to pose a high or very high risk of reoffending, such as those who did not believe abusing children was wrong.
They would be required to receive treatment in the hostels under the conditions of their licence.
The report estimates there were 405 sex offenders under Probation Service supervision and said: "If these offenders in the community were to be immediately offered places in 25-bed residential treatment units, at least 19 such units would need to exist.
"It is clearly unrealistic to suggest that 19 residential treatment units should be operating within the community."
The report says one study showed one in 10 offenders were reconvicted within two years of their 12 months of treatment.
That figure rose to three in 10 of those offenders who did not participate in the treatment programme.
Residents forced a planned Surrey clinic to be dropped
The report makes no mention of where the centres should be located.
Mr Cavadino said: "Sex offenders will be more closely supervised, monitored and treated in these centres than in any other type of community provision.
"By cutting reoffending rates, the centres will reduce the number of children and adults who suffer the appalling trauma of sexual abuse.
"Anyone campaigning against opening such a centre must realise that they may
be increasing danger to the public and the suffering of future victims."
The founder of the National Association for People Abused in Childhood (Napac), Peter Saunders, said: "The huge majority of people who abuse children are never brought to justice and society should be more concerned about that than having a clinic down the road.
"At least [sex offenders] are being treated and supervised."
Harry Fletcher, assistant general secretary of probation union Napo, said: "Ministers need to launch an education campaign to persuade the public that
these offenders should be housed together and not dispersed.
"If it proves too difficult to persuade the public, then the best bet would be non-residential sites away from centres of population."
An attempt to move the Wolvercote Clinic sex offender unit from Epsom to Silverlands in Surrey met with such determined local opposition it was eventually dropped and the clinic closed.
The clinic's former head, Donald Findlater, told BBC Radio 4's Today programme 305 sex offenders had been successfully treated by the clinic.
He said: "No single one of those offenders committed any offence against any local adult or any local child."
Home Office minister Paul Goggins admitted it was a "tricky challenge".
He said: "We know that local communities are afraid and unsure at the prospect of the development of such a centre, but at the same time we know that we can reduce reconviction rates and therefore make our society a safer place.
"If we get the balance right, if we explain, if we can reassure people, then we will overall make our society a safer place to live and that's a goal worth striving for."