The state of Rajasthan is offering prizes including television sets, food processors and even a Tata Nano car for people who agree to undergo sterilisation, a doctor has revealed.

"We want to promote sterilisation," Pratap Singh Dutter, the deputy chief medical officer of the state's Jhunjhunu district has said.

"Everyone who gets sterilised between today and 30 September will be entered into a lottery to win prizes."

The first prize is a Tata Nano and other rewards up for grabs include motorcycles and 21-inch TVs, Dutter said.

"We felt we were falling behind on our sterilisation targets of 21,000 per year, so the district collector came up with this idea. We hope at least 6,000 people will come forward in the next three months to get sterilised," he said.

According to census data released in March this year, India's already billion-plus population is set to grow further in the next few decades and become the world's biggest by 2030, surpassing China's.

The country has a total fertility rate - the number of children borne on average per woman - of 2.588, according to 2010 figures issued by the United Nations Population Fund (UNFPA).

The fertility rate has declined, however, since 1990 when it stood at 4.0, the UNFPA says.

Advocates of family planning have criticised the new rewards-based scheme, calling it coercive and unsustainable.

"We don't favour incentives as a way of encouraging sterilisation, it is coercion by a different name. Besides, how can you sustain it? You can't give a Tata Nano every six months to people," Sona Sharma from the non-profit Population Foundation of India told AFP.

Sharma warned against the rush to meet sterilisation targets.

"They will probably succeed in raising numbers, but the quality of medical care is always compromised in such situations, when you have many patients, few doctors, and limited time, doctors end up cutting corners and the repercussions can be frightening," she said.

Dutter said no one in Jhunjhunu, which has a population of 2.1 million, up 11.8 per cent over 10 years, had complained about the new scheme.

"We are not forcing anyone or taking advantage of them, we are just trying to encourage them to volunteer," he said.

In the past, officials have floated stranger incentives and theories on the best ways to slow down the country's birth rate.

Two years ago Health Minister Ghulam Nabi Azad suggested that late-night television would act as an effective form of birth control, by lulling people to sleep so they would not produce any children.

Although some analysts say India's growing population is a burden and a strain on limited public resources, others say the country stands to make huge economic gains as increasing numbers of young people enter the workforce.

Over the next two decades, the country's working-age population will increase by 240 million - four times the entire population of Britain - according to Deutsche Bank.

Under a best-case scenario, India's youths will boost earnings, savings, productivity and economic growth when they start jobs.

But critics warn that the country does not have enough skilled, literate workers or adequate employment opportunities to match rising expectations.

Experts say that unless the government finds a way to provide education and create jobs for India's growing population, the country's fabled demographic dividend could turn sour.