Asha Devi, the mother of the victim of the fatal 2012 gang rape on a moving bus, speaks to the media as she leaves a court in New Delhi, India. Picture: AP

New Delhi - Four men convicted in the fatal 2012 gang rape of a 23-year-old woman in a moving bus in New Delhi - a crime that shocked the world - will hang on January 22, a Delhi court declared on Tuesday.

Pawan Gupta, Vinay Sharma, Mukesh Singh and Akshay Singh will be executed at the Indian capital's Tihar Jail, where officials had reportedly started preparations for the execution a month ago.

Nirbhaya - "fearless" in Hindi - was the name given by the media to the physiotherapy student, Jyoti Singh, who was assaulted and raped on a bus on the night of December 16, 2012. She died nearly two weeks later at a Singapore hospital.

The court issued death warrants following an application by the parents of the victim to expedite the hanging, saying the Supreme Court and lower courts have confirmed death sentences in judgements since 2013.

Additional Sessions Judge Satish Kumar Arora said the hanging of the four convicts will take place at 7 am (0130 GMT) on January 22, Nirbhaya's father Badrinath Singh told reporters.

"This judgement will reinforce people's faith in the judiciary. My daughter will get justice," the victim's mother Asha Devi said, adding she had waited seven years for justice.

Lawyer AP Singh, who represents convict Akshay Singh, said he will file a curative petition in the Supreme Court within a day or two, requesting the top court to look again at the judgement.

Last month, the Supreme Court dismissed the last review petition in the case, filed by Akshay Singh. The victim's parents had then asked the lower court to issue a death warrant.

The men accused in the rape and murder were first handed death sentences by the trial court in September 2013. It was upheld by the Supreme Court in May 2017.

After their review petitions were rejected in December, the convicts still have the final legal recourse of filing a curative petition in the Supreme Court. If that petition is rejected, they can approach the president of India with a mercy petition to commute the death sentence.

As the judge pronounced the order, the court-room was packed and thick with emotion, broadcaster NDTV reported. Nirbhaya's parents as well as family members of the convicts wept.

The mother of Mukesh Singh, one of the convicts, walked up to Nirbhaya's mother and begged for forgiveness. "I appeal to you to forgive my son. I am begging for his life," she said according to the broadcaster.

The 2012 crime had sparked mass protests across the country and an international outcry.

Six men, including one who was a juvenile at the time of the crime, were accused of brutally gang raping the student and beating a male friend accompanying her.

Ram Singh, who was the bus driver and one of the perpetrators, committed suicide in Tihar jail at the beginning of the trial. The juvenile, was let off in 2015 after three years in a reform home.

Executions are rarely carried out in India - there have been only four such instances since 2004. Yakub Memon, who was convicted for financing and providing logistic support for the deadly 1993 Mumbai bombings - was the last to be hanged - in 2015.

Despite stricter laws and measures to increase security for women since the Delhi gang rape, a high number of such crimes continue to be reported.

According to the latest government data available, 33,658 women and girls were raped in India in 2017. Activists say many more rapes go unreported.

The criminal justice system also fails to respond adequately, with the conviction rate in rape cases at 32 per cent in 2017.

A couple of recent cases, one where a young woman was set on fire by men she accused of rape and later died, and the gang-rape and murder of a young woman veterinarian in Hyderabad have brought the spotlight back on cases of sexual assault on women.

dpa