China will scrap an export duty of 40 percent on metallurgical coke, a steelmaking raw material, from next year, an official with the Ministry of Finance said, in a move that could boost Chinese exports to compete with overseas sellers.

China used to be the world's largest exporter of coke, but its exports have almost dried up since 2008, when Beijing raised the export duty from 25 percent in a bid to reduce pollution.

"There will be no export tariff (for coke) starting from 2013," said the official, who declined to be identified as he was not authorized to speak to media.

The move to scrap coke tariffs followed a ruling by the World Trade Organization in July 2011 that China's export curbs on several raw materials breached free-trade rules. The body has set a deadline of December 31 for China to act.