NEW DELHI: Police formally charged five men Thursday with the gang-rape and murder of a 23-year-old student, a crime which appalled India and led to national soul-searching about the treatment of women.

Police filed a string of charges including murder, rape and kidnapping against the suspects, listing evidence in a confidential 1,000-page document submitted to a district court in the south of the capital New Delhi.

The five aged between 35 and 19, who would face the death penalty if convicted, had been expected in court but were not present when the media were allowed in to listen to part of the proceedings.

"We have filed the charge sheet against the five accused," an investigating police officer told a woman district magistrate. She is expected to transfer the case to a fast-track trial court when the next hearing is held on Saturday.

The medical student from north India was repeatedly raped and violated with an iron bar on a moving bus in the capital on December 16 as she returned from a cinema with her boyfriend.

Protesters have massed in Indian cities daily since the assault to demand the government and police take sex crimes more seriously, with tougher penalties for offenders and even chemical castration among measures being considered.

The latest incident, though far from rare in a country where gang rapes are commonplace, has led to an outpouring of criticism and deep self-reflection in the media and the political class about crimes against women in India.

A statement from the Delhi victim, who died at the weekend from her injuries, and an account from her boyfriend, who was badly beaten during the attack, are expected to form crucial parts of the evidence against the five.

A sixth suspect who is believed to be a minor aged 17 was not charged in the court at Saket on Thursday. Detectives are awaiting the results of a bone test to verify his age and determine whether he can be tried in an adult court.

The trial of the men, who were allegedly drunk when they took the private bus out for a joyride, is to be held in a special fast-tracked court aimed at avoiding the delays typical of India's dysfunctional justice system.

Amid public clamour for the guilty to be executed, Altamas Kabir, the country's chief justice, has cautioned against letting 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," Kabir was quoted as saying in the local media on Thursday.

Lawyers at the district court in New Delhi have refused to defend the suspects, meaning the government will have to appoint advocates for them.

Several hundred protesters including female lawyers gathered outside the court on Thursday demanding greater protection for women and a better justice system.

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

Just 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.

Analysis of the Delhi gang-rape has focused on India's deeply patriarchal society, in which misogyny and sexism run deep and women are often treated as second-class citizens.

Amid a wide-ranging national debate seeking to identify the reasons for the horrifying violence, women's rights groups have highlighted the difficulty rape victims face in securing convictions and dealing with social stigma.

"Every 25 minutes there is a rape case in India, but only one out of ten cases gets reported," activist Ranjani Kumari told AFP. "How long should people have to wait for the system to respond?"

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.

Campaigners hope the December 16 attack will serve as a turning point, changing social attitudes and leading to greater sensitivity by the police.

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 unidentified victim.

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

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.