India's federal government is to deploy thousands of retired defence personnel to provide security to overseas tourists following at least seven cases of alleged rape and molestation of foreigners, including four Britons, this month.

The decision came within hours of police confirming that medical tests had established that a 32-year-old British woman had been raped in Goa, one of India's most popular tourist destinations on the west coast.

She had reportedly been raped after accepting a lift home on her assailant's motorcycle after attending a concert in Mapusa, in north Goa.

In a separate incident, Goa police said that two British women claimed to have been sexually assaulted by the owner of a resort in the former Portuguese enclave, but a case had yet to be registered against him.

Reports of a British freelance journalist being raped a fortnight ago in Udaipur, the city of lakes in the western desert state of Rajasthan, which is also popular with foreigners, generated more negative publicity for India.

"It has been decided that the large bank of trained, disciplined ex-servicemen in the country can be utilized to provide security to tourists," federal tourism secretary Shilbhadra Banerjee said.

Some 60,000 Indian defence personnel retire each year.

The provision to "fast-track" tourist rape cases is also being introduced in a country infamous for its slow justice system.

Other deterrent measures being introduced include dedicated phone numbers for security in all major tourist spots.

Around four million tourists, many of them Westerners, visit India a year. Tourism officials conceded that these incidents of rape and molestation underlined the pitfalls of Western women in India where they are generally presumed promiscuous.