The couple was camping at Jhadia village in Datia district, more than 400 kilometers (250 miles) north of capital city Bhopal, late Friday night, when they were attacked by a gang of eight to 10 men, the Hindustan Times reported.
The 39-year-old woman and her husband were on a cycling trip to Seonda, a tourist spot in Datia district, from Orchha, another tourist spot in Madhya Pradesh, when they decided to camp near the village for the night. The couple was planning to visit Agra in neighboring Uttar Pradesh to see the Taj Mahal.
The assailants overpowered the husband before gang raping his wife in his presence.
The victim was rushed to Gwalior, about 100 kilometers from Bhopal, and tests in a hospital confirmed rape, police sources said.
The tourists told police that their camera, 10,000 rupees ($185) in cash and a laptop were stolen.
Twenty people have been detained as suspects and are being questioned, Chambal Range Deputy Inspector General of Police D.K. Arya told Zee News.
The Swiss Embassy called for a speedy probe into the incident and has been in touch with authorities in Madhya Pradesh.
Swiss Ambassador Linus von Castelmur spoke to the woman and assured her of all help.
"The embassy is most distressed with the gang rape of a Swiss national in Madhya Pradesh. The ambassador has been able to speak to the victim and her partner and has assured them of all possible support. Their health and treatment is the priority of the moment,” the embassy said in a statement.
"The embassy has also been in touch with the local authorities and has requested for swift investigation and for justice to be done," the statement said.
The incident comes three months after the gang rape and murder of a woman in the capital in December, which sparked massive protests across India.
The prime suspect in that case was found dead on March 11 in New Delhi’s Tihar Jail. Authorities have launched an investigation into the death, while the rape trial continues on a fast track in New Delhi.