China will introduce a special value-added tax invoice for the rare earth sector "as soon as possible" in order to further crack down on the illegal mining and over-exploration of rare earths, a government official overseeing the sector said Wednesday.

Jia Yinsong, chief of the Rare Earth Office of the Ministry of Industry and Information Technology (MIIT), made the remarks at a press briefing in Beijing, without specifying the date when the invoice will be launched.

Jia said that China will intensify efforts to crack down on the illegal mining and smuggling of rare earths as over-exploration causes great damage to the environment.

China is the world's largest producer of rare earth metals. The country currently produces more than 90 percent of the world's rare earth metals, but its rare earth reserves only account for about one-third of the world's total.

Lured by high profits, illegal mining and smuggling cases continue in the country despite the government's enhanced striking efforts.

Multiple ministries, including the MIIT and customs authorities, have launched inspections on a total of 25 rare earth miners and 99 rare earth processors since Nov. 11 this year.

The checks showed an improving situation as illegal mining, over-exploration, environmental pollution, and smuggling have been curbed, Jia said, adding that these problems have not yet been rooted out.

He said that during the first nine months of this year, production output from rare earth smelting was down 7 percent year-on-year, while prices of rare earth products rose by as much as four times the level at the beginning of the year.

Exports of rare earth products during the period were also down 65 percent. Jia said this was due to the changes in the overseas market and stronger domestic requirements for environmental protection.