Indian police are searching for a driver from the international taxi-booking service Uber for allegedly raping a young woman in the capital.

The driver allegedly sexually assaulted the 25-year-old woman before threatening to kill her if she alerted police.

Investigators found a taxi that was abandoned by the 32-year-old driver but are still looking for him, Alma Ming, a New Delhi police officer, said.

The woman, an executive for a finance company, dozed off in the taxi as she was returning home from dinner with friends on Friday night, media reported on Sunday.

The woman has told police she woke to find the taxi parked in a secluded place where the driver assaulted and raped her, before dumping her near her home in north New Delhi.

The woman clicked a photograph of the car's number plate and then reported the crime to police, an officer told the Press Trust of India news agency.

"We have identified the cab company and the driver, who is in his mid-30s. Raids are being conducted to nab him," the officer said.

US-based Uber is gaining popularity in India, especially among young, urban workers who use its smartphone app to connect with and pay for local drivers.

The alleged attack is a blow to Uber's reputation in India, where women are extremely safety-conscious after dark following a string of rapes that led to global shock and anger.

Uber's statement

Uber says it is working with police to solve the "terrible crime", while the driver's licence has been suspended.

"Our thoughts are with the victim of this terrible crime and we are working with the police as they investigate," Evelyn Tay, an Uber spokesperson, said in a statement.

"Safety is Uber's highest priority and in India we work with licensed driver-partners to provide a safe transportation option."

The fatal gang-rape of a student on a moving bus in New Delhi in December 2012 stirred outrage about the high number of attacks of women in India and inadequate efforts to keep them safe.

The nationwide outcry led the federal government to rush through legislation doubling prison terms for rapists to 20 years and criminalising voyeurism, stalking and the trafficking of women.

The law also makes it a crime for officers to refuse to open cases when complaints are made.

Official statistics say about 25,000 rapes are committed every year in India, a nation of 1.2 billion people.

Activists, though, say that number is just a tiny percentage of the actual number, since victims are often pressed by family or police to stay quiet about sexual assaults.

Source: Agencies