Child victims of sexual abuse in India are often mistreated and humiliated by police, says the US-based Human Rights Watch (HRW) in a new report.
Government systems to deal with the issue of abuse are inadequate, it says.
The report says sexual abuse is "disturbingly common" in Indian homes, schools and care homes.
The Indian government has made no public comment about the report's findings - it does not respond to such reports as a matter of policy.
A government study in 2007 reported that two out of every three children in India were physically abused and that 53% of the nearly 12,300 surveyed children reported one or more forms of sexual abuse.
Other reports say more than 7,200 children, including infants, are raped every year in India. Child rights activists believe many more cases go unreported.
'Dismissed, ignored, mistreated'
The 82-page report - Breaking the Silence: Child Sexual Abuse in India - was released in the Indian capital, Delhi, on Thursday morning.
It says that the authorities are failing to protect children both from sexual abuse and also when it comes to treating victims.
"Children who bravely complain of sexual abuse are often dismissed or ignored by the police, medical staff, and other authorities," said Meenakshi Ganguly, South Asia director of HRW.
The report says that many children are "mistreated a second time by traumatic medical examinations and by police and other authorities who do not want to hear or believe their accounts".
It says that government efforts to tackle the problem, including new legislation to protect children from sexual abuse, will also fail "unless protection mechanisms are properly implemented and the justice system reformed to ensure that abuse is reported and fully prosecuted".
Campaigners say children are sexually abused by relatives, neighbours, at school and at care homes for orphans and that most of the cases go unreported because in India's traditional system, parents and families are afraid of attracting social stigma.
In May last year, India's parliament passed the Protection of Children from Sexual Offences Act which, for the first time ever in the country, made all forms of child sexual abuse a criminal offence.
This law made it possible for an abuser to be prosecuted for molestation and non-penetrative sex, in addition to rape.
Until then, many abusers could escape punishment because non-penetrative sex was not recognised as rape. The law also shifted the burden of proof onto the abuser and recommended setting up special courts to try cases of child abuse.
But campaigners say that better laws alone will not help - what is needed is a change in the prevailing social attitudes and the way the police, medical officials and the judiciary deal with cases of sexual abuse of children.