Seven relatives of a 75-year-old widow have been arrested by police for standing by and watching while she burnt herself to death on her husband's funeral pyre.

Lalmati Verma's three sons, their wives and her daughter were arrested for "abetting the act" earlier this week following the her death this weekend in Chechar, a village in Chattisgarh state in central India.

"Their mother had clearly announced her intention of jumping into her husband's funeral pyre, when her husband was still alive but very ill," said Amit Kumar, the local superintendent of police. "These relatives failed to inform the police, or even other villagers, of her intention, and are thus guilty of abetment."

The seven were arrested under the Prevention of Sati Act and face possible capital punishment or life in prison, Kumar said. Under the law, authorities can punish anyone who promises financial or spiritual benefits to a woman's family for committing sati.

The law is punitive; anyone who is found guilty of standing aside as a woman throws herself onto a funeral pyre can be sentenced to life in prison.

Police said that Lalmati's actions had been pre-planned. She had come for the funeral of her husband dressed in a bridal sari. Before killing herself, she made a couple of rounds of the pyre holding a coconut and a copy of a Hindu holy book.

Bharat Ram, the eldest son, had earlier told reporters his mother's decision was her own. "No one forced her or incited her to commit sati," the Hindustan Times newspaper quoted him as saying.

The practice of sati, where a Hindu wife immolates herself on her husband's pyre, has been banned in India since 1829 and was considered by British officials as a medieval throwback. It originated with Hindu women who chose to kill themselves rather than be taken prisoner after their husbands fell on the field of battle.

It is now rare but does occur in poor, rural areas where villagers revere the practice as the ultimate demonstration of female honor, devotion and piety.

Newspapers reported that a large number of villagers gathered at the site of Lalmati's sati and that verses from Hindu sacred texts were recited all night.

A small sati temple already exists near the site in Chechar in memory of Jheek Bai, a woman of the same village who had committed sati nearly four decades ago.