Eight women have died in India and dozens are in hospital, many in a critical condition, after a state-run mass sterilisation.

"Since Monday eight women have died and 64 are in various hospitals," said Sonmani Borah, a government official in the state of Chattisgarh, where the sterilisation camp was held.

Some 83 women underwent laparoscopic tubectomy operations at a family planning camp organised by the state government.

Dr Kamalpreet Singh, director of the state's health services, said: "Certainly there was some lapse somewhere. We are trying to find out its causes."

The camp was held in the constituency of the state's Health Minister Amar Agarwal, who said: "We've ordered a probe and the post-mortem reports are expected tomorrow."

After the operations, which took around five hours, the women were discharged but soon began complaining of severe pain and fever.

Their conditions deteriorated rapidly and they were transferred to another hospital, where eight women died.

Under the state government's population planning programme, a woman is given 1,400 Indian rupees for the operation.

Health workers who bring women to the camps get a 200 rupee commission.

Sona Sharma, joint director of advocacy group Population Foundation of India, told Sky News: "Monetary incentives is a form of coercion of these weaker and marginalised women.

"Women are on the frontline of population control as their lives can be put to risk, while the men can't risk an operation. It is a social issue as well."

Family members have complained that too many surgeries were carried out in one day.

Ms Sharma added: "The quality of care and operations are very poor at most of these camps.

"Rates of infections are very high. Though there are standard operating procedures, in the rush to achieve targets by health officials these procedures are never followed." 

The state government has announced compensation of 200,000 rupees for the families of those who died, and 50,000 rupees for those in a critical condition.

India carries out 37% of the world's female sterilisation, the highest proportion of any country.

According to government data, 4.6 million women were sterilised last year, but despite that figure India has missed every population control target in the last 50 years.

Every year 18 million people are added to the 1.2 billion population. At that rate it would surpass that population of China by 2021.