The exiled Bangladeshi writer Taslima Nasrin, who is accused of insulting Islam, will be allowed to stay in India it emerged today – but only if she remains in a government flat in a secret location in Delhi, unable to receive visitors or step outside her door.

The Indian foreign affairs ministry justified the conditions saying that as a "guest" Nasrin should not "undertake actions that could hurt the sentiments of the many communities that make up our multi-religious and multi-ethnic nation."

Speaking via email from her safe house in Delhi today, Nasrin rejected the Indian government's description of her as a "guest", emphasising that she has been a resident in India since 2004.

"The Indian constitution upholds democracy, secularism, human rights and freedom of expression, exactly what I have been fighting for," she said. "I think this warning goes against freedom or expression, which is a vital part of democracy."

Nasrin fled her adopted home of Kolkata in November after Muslims protested violently against "anti-Islamic" passages in her works. The rioting was brought to an end only when the army was deployed in the city – and the writer forced to flee.

The 45-year-old told the Guardian that she had been told her "residency permit" would be extended just days before it expired, but for an unspecified time. Her only company is a television and her laptop.

"I cannot live a normal life like this. [Officials] said because if I went outside 10 people would die in riots. I don't believe them," said Nasrin. "I want to stay in India but I don't know how long they will allow me to remain."

Nasrin said she was a "prisoner without prisoner rights".

"I get food and medicines bought to me. It is prison food. I want prisoners' rights. Let me have visiting hours."

Lawyers today questioned whether such a "detention" was legal under Indian law. Indira Jaisingh, a supreme court lawyer, said the government had probably used a 1946 "foreigners' act" to restrict the writer's movements.

"I think it is almost certainly illegal and could be challenged in the courts. The act is usually used for criminals wanted by the police. Here it has been used pre-emptively but not proportionately. The constitution guarantees freedom of life and liberty to anyone on Indian soil."

The British author Hari Kunzru, who is an executive member of the writers' organisation English PEN and has been in regular contact with Nasrin during the last few months, described the Indian government's position as a "mixed blessing".

"She's not being put back into immediate danger," he said, "but there seems to be a lack of political will to do anything about her situation. The Indian government is trying to kick this problem into the long grass rather than deal with its responsibility to uphold freedom of expression."

He said he held out little hope that her state of "suspended animation" would improve.

"Unless somebody in the Indian government is prepared to take a political risk, standing up to say why she should be defended," he said, "this could go on indefinitely. I'm frankly not very hopeful that somebody will do that."

"She's a defiant, strong woman who has lived for a long time with a real threat of violence, so she's used to it," he continued, but "indefinite detention is a form of torture."

Earlier in the week, intellectuals had called on the government to give the writer citizenship and permanent residency in India, saying it was the state duty to protect "freedom of speech".

Nasrin, who has lived in India since 2000, has been targeted by radical Muslim groups in the past six months over her autobiography, Dwi-Khandita, where she commented on the relationship the prophet Muhammad had with his dozen wives and also said that the Qur'an had advised against friendships with non-Muslims.

The book had been recalled and the passages deleted at the end of 2007.

"[Dwi-Khandita] was basically defaming the Prophet," said Mohammad Anwer, spokesman for the Jamia Ulama-i-Hind which runs thousands of religious schools in India. "It is best she is forgotten about. Let her abide by the government's conditions."