The sexual abuse of British girls of South Asian origin is going unreported because authorities tend to focus on gangs that target white youngsters, according to a study released on Tuesday.

Although there has been a series of high-profile British court cases in which men of South Asian heritage were convicted of sexually exploiting vulnerable white girls, authorities are failing to spot cases in which men target girls from their own ethnic group, the Muslim Women's Network UK said.

Asian girls are reluctant to report sexual abuse to the police because they fear that they will not be believed or that they will bring dishonour to their families, according to the group, which advises the British government on issues facing Muslim women.

The Muslim Women's Network said it had uncovered 35 cases in which young Asians had been sexually exploited. Most of the victims said their abusers were men from the same ethnic group.

Haleh Afshar, the group's president, said there had been a "deafening silence" on the sexual abuse of young Asian girls.

"In all communities victims of such violence find it difficult to report sexual abuse and seek support. Among Asians and Muslims this is exacerbated by a culture of honour and shame," she wrote in a foreword to the report.

The group was unable to speak directly to the victims but said it had collected evidence from charities who had contact with them, as well as police, healthcare workers and other officials.

Sue Berelowitz, Deputy Children's Commissioner for England, said there was a widespread myth that gangs of Asian men were targeting only white girls, motivated by "hatred and contempt for white females".

In reality, sexual predators target the most accessible victims -- often those from the same ethnic background, she added.

The group admitted that it is difficult to estimate the scale of the abuse, and stressed it was also not clear whether or not Asian girls face greater exploitation than their white schoolmates.

Most of the victims were aged under 16 and two thirds of them were from Pakistani families, the report said.

Some of the girls were plied with drugs or alcohol before being passed around gangs of men, in cases similar to those involving white girls that have hit British headlines in recent months.