NEW DELHI (Reuters) - India needs to curtail excessive medical care that leads to patient overspending as more people get health insurance, the World Bank said on Thursday, adding voice to a growing chorus against overtreatment in the country.

Practices such as "defensive medicine" and aggressive marketing by hospitals, which cost the United States an estimated $250 billion to $300 billion annually, are emerging as a serious problem in India, the Washington-based institution warned.

The comments come as India's new government has vowed to crack down on unethical practices that plague India's $74 billion healthcare industry, where doctors say getting kickbacks for referring patients or passing inflated hospital bills to insurers is widespread.

The World Bank warned that as more people are able to afford healthcare and the government ramps up insurance coverage, the risk of excessive care may increase, in notes released from an April meeting with policymakers and insurers.

Awareness of how get a medical claim remains low in India and out-of-pocket expenses remain high. While more than 630 million people are forecast to have some form of health insurance by next year, more than half the country will remain uninsured.

Prime Minister Narendra Modi's government is also working on what may be the world's largest health insurance program, partially inspired by the "Obamacare" law in the United States.

As more and more patients become insured, the size of their bills may grow, the World Bank said. "Individuals in India with private voluntary health insurance are two to three times more likely to be hospitalized than the national average."

Some doctors in India have already joined the movement. Last month, the All India Institute of Medical Sciences convened a "Society for Less Investigative Medicine," which puts the onus on both doctors and patients to tackle the problem.

The society's founder, Balram Bhargava, said it was not ideal that Indian doctors adopted the so-called American medicine practice of taking a defensive strategy of doing checkups to avoid patient litigation.

UNHEALTHY PRACTICES

Last week, Health Minister Harsh Vardhan called for tougher laws in the health sector after a television news channel reported that some laboratories allegedly offered kickbacks to doctors who referred patients to their diagnostic centers.

Some doctors complain unethical behavior is more rampant in the vast sector of private health care providers that capitalize on low spending in the public health system. Private health providers have created 80 percent of the new hospital bed capacity in the last decade, according to PwC-NatHealth report.

Malpractice, such as falsifying patients' diagnoses to pass unnecessarily high bills on to insurers, led one worker in private health to quit his job in favor of a low-paying government health service job.

"I quit because there was dirt there," said Sunil, who declined to give his last name or the name of the hospital he left. "Such practices did not suit my conscience."

Arun Gadre, an associate coordinator at the non-profit organization SATHI, is publishing a book featuring interviews with dozens of doctors in the private sector.

"The medical private sector has stooped to such low levels just to earn money," Gadre, himself a doctor, said.

"One nephrologist working in a corporate hospital was asked by his CEO for an explanation why a person was discharged without kidney biopsy, even though no operation was actually required."