Two men are in court after the Observer investigation into tourist visits to view tribes people

British and international tour operators have been warned that they will face prosecution if they continue to offer "human safaris" to India.

Three Indian tour operators have already been charged in connection with the Observer's investigation into "human safaris" and two men are facing up to seven years in jail if convicted.

But the tour operators have hit back, accusing independent foreign travellers of breaking rules and giving tour firms a bad name.

Last week's Observer investigation of safaris to see the Bonda tribe of Orissa prompted an immediate response from the state's government, with the chief minister ordering an inquiry and sending a senior official to investigate.

Police in the state capital, Bhubaneswar, raided the offices of Dove Tours – named in the Observer report – and registered a case against the company for "selling products in [an] obscene manner in public". In a statement Orissa police said: "We have registered a case against a city-based tour operator after finding its brochures and website containing certain objectionable material." The company denies the allegations.

Tourists were barred from visiting Bonda villages in 1989 after reports that some had been taking photographs of naked members of the tribe. The Observer investigation found that travel agents were getting around the law by taking tourists to view them at the weekly markets they attend. Some promoted the tours with references to the scanty dress of Bonda women. Several tour companies have since removed offending offers from their websites.

Orissa's culture secretary, Ashok Tripathy, said Orissa welcomed "rich and enlightened" tourists who treated the tribe with respect. "Cheap offers mentioning that Bondas roam naked", and the prospect of photographing, them should not be used to lure tourists, he said. He warned tour operators that they would be prosecuted if they continued to use "obnoxious" methods to promote tribal tourism.

However, Gagan Sarangi, director of Dove Tours, defended local operators, putting the blame on independent travellers. He told the Times of India: "There are foreigners visiting the tribal areas independently. Since visits to Bonda areas are permitted up to the weekly markets, many avoid taking the help of tour operators. Such people are unaware of basic rules, end up hurting the sentiments of people and give a bad name to our profession," he said.

Yet in the Andaman Islands – where the Observer first exposed the scandal of human safaris to see the protected Jarawa tribe, and women being forced to dance in return for food – tourists continue to pour through the jungle, despite promises by the Indian government to crack down on tours.

On Thursday two men – Rajesh Kumar Vyas and Sarjeet Singh Guddu – appeared in court in Port Blair charged with organising a trip into the Jarawa reserve which was highlighted in the Observer investigation. They were remanded in custody for two weeks and could face up to seven years in jail.

Police said that taking a foreigner into the Jarawa reserve amounted to "intentionally insulting with the intent to humiliate a vulnerable primitive tribe of these islands".

Professor Anvita Abbi, a linguist, said the Jarawa were in danger of going the same way as the Great Andamanese tribe, who once numbered 5,000 but are now down to 56 people. Two years ago the last speaker of the Bo language – one of 10 spoken by the tribe– died.

Stephen Corry, director of Survival International, which campaigns on behalf of tribal peoples, said: "At a time when evidence of human safaris has prompted global outrage, it's vital the Indian government closes the Andaman Trunk Road." The road cuts through Jarawa territory making it easier for tourists to contact the tribe.

The Association of British Travel Agents has defended tour operators, insisting that most act responsibly and that tourism can bring economic benefits to indigenous people. Spokesman Sean Tipton said: "It is important that any interaction between tourists and indigenous people happens with the prior consent of the indigenous people."