Five men accused of gang-raping a 23-year-old student on a moving bus in New Delhi in a deadly crime that repulsed the nation are to be formally charged in court on Thursday.

Police will lay out evidence against them of rape, kidnapping and murder after the woman died at the weekend from her horrific injuries inflicted during an ordeal that has galvanised disgust over rising sex crimes in India.

The men, mostly residents of New Delhi slums, will face the death penalty if convicted, India's Home Minister Sushilkumar Shinde has said, amid public clamour for their execution.

"It is compulsory for all the accused to present themselves before the magistrate," explained Rana Dasgupta, a legal officer at the Saket district court complex where armed police maintained tight security on Thursday morning.

The magistrate, working from a small room with 30 chairs, "will admit the charge sheet presented by the police and then give a copy of the charge sheet to all the accused", Dasgupta added.

This document -- reportedly 1,000 pages long -- will detail the evidence collected, the most powerful of which is expected to be a statement from the victim after the attack and an account from her boyfriend who was with her at the time.

He was beaten during his attempts to save the medical student after the couple were lured onto the private bus by the reportedly drunk gang after watching a film at night.

A sixth suspect in the case who is believed to be a minor aged 17 will not be charged in the Saket court on Thursday, a Delhi police spokesman told AFP. Detectives are awaiting the results of a bone test to verify his age.

The trial of the suspects has been fast-tracked and Altamas Kabir, the chief justice of India, has cautioned against letting public anger overwhelm the due process of the law.

"Let us not get carried away. A swift trial should not be at the cost of a fair trial," chief justice Kabir was quoted as saying in the local media on Thursday.

Lawyers at the district court in New Delhi have decided they will not defend the suspects, meaning that the government will have to appoint advocates for them.

As a number of petty crime cases proceeded in court in the morning, several hundred protesters including lawyers gathered outside demanding greater protection for women and improvements in the dysfunctional justice system.

"Why is there such a low conviction rate in India? Please judges, wake up!" said one banner.

A total of 26 percent of the 24,206 cases of rape registered in 2011 in India resulted in a conviction, according to the National Crime Records Bureau.

Protesters have massed in Indian cities daily since the December 16 assault demanding the government and police take sex crime more seriously, with tougher penalties for offenders and even chemical castration being considered.

The latest incident, though far from rare in a country where gang rapes are commonplace, has led to deep soul-searching in the media and the country's political class about the treatment of Indian women.

Analysis has focused on the deeply patriarchal Indian society, in which misogyny and sexism run deep and women are often treated as second-class citizens, as well as the difficulty of rape victims in dealing with social stigma and the police.

On December 28, it emerged that a 17-year-old girl had committed suicide after police allegedly tried to persuade her to drop a complaint of gang-rape and instead either accept a cash settlement or even marry one of her attackers.

There is hope, however, that the December 16 attack will serve as a turning point in helping to change social attitudes and lead to greater sensitivity in the police.

Amid daily reports of new horrific sex crimes, a member of the ruling Congress party was detained in the northeastern state of Assam on Thursday after being accused of raping a girl in a remote village, police said.

In scenes played out on national television, village women were seen stripping the lawmaker, Bikram Singh Brahma, and repeatedly slapping him.

The government has set up three separate commissions to look into the New Delhi gang-rape and suggest changes in the law, with one minister suggesting new anti-rape legislation should be named after the unnamed victim.

The brother of the victim, speaking from the family's home village in northern Uttar Pradesh state, said they would not object if the government wanted to name a new law after her.

"It will be like a tribute in her memory," he told the Indian Express newspaper, while also pleading that the family be left alone to grieve their loss.

A recent poll found India to be the worst in the G20 group of nations for women because of child marriage, abuse and female foeticide, which has led to a badly skewed sex ratio in the country of 1.2 billion people.