A court in India has set an execution date for four men convicted of the 2012 gang rape and murder of a woman on a New Delhi bus in an attack that sent shockwaves across the world.

Key points: The four convicts are order to be hanged on January 22 at 7:00am

The four convicts are order to be hanged on January 22 at 7:00am The mother of the victim said she finally will get justice

The mother of the victim said she finally will get justice The lawyers of the four convicts plan to launch last-ditch legal challenges

The four men, Akshay Thakur, Pawan Gupta, Vinay Sharma and Mukesh Singh were convicted in 2013 for the rape, torture and murder of the 23-year-old physiotherapy student, a case that triggered large protests across India.

The victim known as Nirbhaya was gang raped and attacked with a metal bar on a bus before being dumped on the side of the road.

She died in hospital 13 days after the attack in December 2012.

New Delhi court's judge Satish Kumar yesterday ordered the four convicts on death row to be hanged on January 22 at 7:00am, Al Jazeera reports.

The order came after the parents of the victim asked the court to seek death warrants against the four men.

"We have fought the legal battle with a lot of patience for more than seven years. Now, I finally get justice," the mother of the victim, who cannot be named under Indian law, told reporters after the order was handed down.

In 2017, India's Supreme Court had upheld death sentences against the four men.

The BBC reports that lawyers of the four convicts plan to launch last-ditch legal challenges.

A demonstrator holds a placard protesting to protect women in India. ( Reuters: Danish Siddiqui )

In the past two years, the top court has dismissed review pleas filed by the convicts, paving the way for the execution.

The attack prompted India to enact tough new laws against sexual violence, including the death penalty for rape in some cases, but implementation has been poor and the attacks have shown no sign of let-up.

Despite tough laws against sexual violence, a woman is raped every 20 minutes on average in India.

Lengthy trials, often a result of fewer courts and judges, tend to delay convictions, leaving poor, disillusioned victims with little money and patience to pursue the cases.

A 23-year-old rape victim, who was set on fire by a gang of men, which included her alleged rapists, died in a New Delhi hospital last month, prompting protests.

ABC/Reuters