India, the world's biggest sugar consumer, is likely to raise import duty on the sweetener to 50 percent from 40 percent in an attempt to restrict the cheaper flow of the commodity from overseas, a government official said on Friday.

"There have been some apprehensions of cheaper imports flooding the Indian market. That's why the government is likely to raise the duty to 50 percent," the official, who did not want to be identified, said.

The government in April allowed the duty-free import of 500,000 tonnes of sugar by the end of June to keep a lid on prices after local production fell by a fifth from a year ago.

However, in 2017/18 marketing year starting from October 1, India's sugar output is expected to jump a quarter from the previous year to 25 million tonnes.