Six men were due to appear in court on Monday over the gang-rape and robbery of a Swiss cyclist holidaying in India, an assault which has raised alarm about the safety of tourists.

"We have detained all the six persons and they will be produced before the magistrate after lunch today. We will ask for a police remand for five days for all of them," M.L. Dhody, a local police official in the central state of Madhya Pradesh, told AFP.

Five of those arrested, all farmers in their twenties, were paraded in front of television cameras in the state late on Sunday. They were dressed in jeans and shirts but with black cloth covering their faces.

A sixth man was detained in a neighbouring state overnight and brought back to the remote district of Datia, about 400 kilometres (250 miles) south of New Delhi, where the men will be produced before a local magistrate.

Only four of them will be charged with gang-rape, which carries a minimum sentence of 10 years, because testimony from the 39-year-old Swiss victim said two of them were "only present at the crime scene", Dhody said.

All the men face robbery charges as police say the group stole a laptop, a mobile phone and 10,000 rupees ($185) from the victim and her 30-year-old husband, who was tied up before the sexual assault.

"The six of them have confessed to their roles in the crime," Dhody said.

The confessions will likely be inadmissible as evidence during the trial because Indian law treats such statements to police as inherently unreliable.

The victims arrived in the country last month and were cycling through northern India on a trip that would take them to the Taj Mahal city of Agra.

The suspects allegedly saw the pair pitching their tent on Friday night in a remote forested area in Datia district and attacked them.

After being treated in a local hospital, the couple are now in the capital recovering.

They have "expressed their readiness to fully cooperate in the ongoing investigation and identification process. They will continue to stay in India for the moment," a Swiss embassy statement said on Monday.

Last month the Swiss foreign ministry issued an advisory for its nationals travelling in India, warning that sexual violence was on the rise across the country.

The latest incident, carried on the front pages Monday of major Indian newspapers, comes three months after the fatal gang-rape of a 23-year-old physiotherapy student on a bus in Delhi.

That attack spurred outrage and countrywide protests over the treatment of women in Indian society and the inadequacy of laws dealing with sexual crimes.

Under a new bill approved by the cabinet last week, rapists face a minimum 20-year jail term and the death penalty if the victim dies from injuries or is left in a persistent vegetative state.

In January a South Korean student holidaying in Madhya Pradesh said she had been raped and drugged by the son of the owner of the hotel where she stayed.

The home minister of the state complained over the weekend about foreign tourists not informing local police about their movements as required.

"This is the system but it is not being followed," the Press Trust of India news agency quoted Uma Shankar Gupta as saying.