Paul Boateng, the Home Office minister, released the findings in a report which called for greater efforts to be made to protect children.
The report concludes: "Judging by the numbers of cases reported to the police, sex offending against children may be even more prevalent than population surveys have indicated previously."
The findings coincide with reports that the convicted paedophile Robert Oliver has managed to re-establish contact with a ring of child-sex offenders. Although Oliver has agreed to remain under voluntary supervision in a secure hospital unit in Buckinghamshire, he cannot be prevented from communicating by letter or telephone with contacts in what is described as "an extensive paedophile network".
Public concerns over child sex abuse have risen in the past 18 months after the release of a succession of paedophiles such as Oliver, who was jailed in 1985 for his part in the sexual torture and killing of 14- year-old Jason Swift.
Yesterday's report, called Sex Offending against Children: Understanding the Risk, makes clear that the vast majority of young victims of sexual abuse are assaulted by people they know. Mr Boateng said: "Sex abuse by a stranger is of great concern to the public, but the report shows that abuse within the family, or by an individual who has a relationship based on trust with the child, is more common."
The report finds that the victims of attacks by someone from within the home are likely to suffer worse lasting damage than those suffering a one-off attack by a stranger.
Nearly 70 per cent of sex offenders attack only female victims and most act alone.About a third of all sex crime is committed by adolescents, and up to 5 per cent by women, most of whom act in partnership with a male offender. Some 20 per cent of sex abusers go on to reoffend, which is a smaller recidivist figure than for most types of crimes.
According to police estimates there are 72,600 cases of child sex abuse a year. But more detailed research within five forces found 4,369 such offences in a year, despite there being only 3,957 offenders convicted in the entire country in the 12-month period.
The report notes: "Official statistics not only under-estimate greatly the number of sexual offences against children, they also have the potential to mislead in terms of patterns of sexual crime."
The number of people being cautioned or convicted for sex offences declined steadily between 1985 and 1995. But the report says this "could be attributed to the fact that the age of child victims is now being recorded less often and so the true figure is even more masked than it was previously".
The authors call for greater vetting of adults who work with young people, and state that "children need to be educated on how to respond to adults who seek to abuse them, and on what they should do if friends tell them `secrets' about abuse they are experiencing".Reuse content