Setting up the register and monitoring the sex offenders is costing the police in England and Wales about pounds 500,000 a month. The total cost so far is more than pounds 6.5m.
Figures from the police, however, show that most sex offenders - 6,262 or 95 per cent of those registered in the first year - have informed the authorities about their movements.
The Sex Offenders Act came into force in September last year in response to alarm at the lack of information on and monitoring of paedophiles once they were released.
Under the Act, an estimated 6,615 sex offenders who were either being released from jail under licence, or who received a community sentence such as probation, must within 14 days inform the police of their address, or whether they have moved, or changed their name.
Failure to comply with the new law is punishable by a maximum of six months in jail. But despite the publicity surrounding the new powers only a few offenders who failed to be registered have been punished so far. Several have been jailed for the offence.
Tony Butler, the Chief Constable of Gloucestershire and vice-chairman of the Association of Chief Police Officers' crime committee with responsibility for the management and monitoring of sex offenders, said that in the first year the Act was implemented, 353 offenders had not registered.
Some have never registered, some have moved address and not informed the police, and some may have gone abroad and do not need to register. The Home Office is drawing up plans to block this loophole for "foreign sex holidays".
Mr Butler argued that this figure compared favourably with the United States where compliance rates range from 30 per cent in some states to 85 per cent at best.
The annual cost of implementing the Act is expected to exceed pounds 7m. Mr Butler added that a significant extra expense has been the cost of policing high-profile paedophiles. For example, the release of the notorious sex killer Sidney Cook cost Avon and Somerset police pounds 150,000 in managing public disorder.
There are an estimated 260,000 convicted sex offenders in the UK, 110,000 of whom have offended against children, but as the legislation is not retrospective most do not have to register.
Harry Fletcher, assistant general secretary of the National Association of Probation Officers, argued: "The authorities have done well to get nearly all the names to register, but it still only represents 5 per cent of known offenders."
Meanwhile, a further measure to prevent people convicted of sex crimes from reoffending comes into power today. The Sex Offender Order will allow courts to ban convicted offenders from going near specified places, such as schools, and from specified activities, such as joining a Scout group.
Breach of the order, which will last five years, can lead to a maximum five-year jail term.
Police officers can apply for an order against any sex offender whose activities give cause for concern.Reuse content