The country's agriculture authority has urged its local branch in Hebei province to crack down on the use of banned and hazardous additives, which were allegedly fed to sheep as a way to produce more lean meat, China Daily reported.

"A special investigation will be launched (into) illegal acts related to banned additives, such as production, sales and use. People involved in such illegal practices will be punished severely," a press official from the Ministry of Agriculture said on Friday.

The official commented after media reports last week said that clenbuterol, a banned additive, had been illegally fed to sheep in Changli and Lulong counties in Hebei province for many years.

Clenbuterol, which is better known as "lean meat powder", can speed up muscle-building and fat-burning, resulting in leaner meat.

However, local breeders commonly fed the banned additive to sheep in Changli and Lulong counties, the Beijing News reported on Aug 16.

"More lean meat, more money. For instance, 100 sheep fed with Clenbuterol can be sold for 2,000 yuan (US$312.87) higher in total than ordinary sheep," a local breeder who uses the pseudonym Sun Guozhong told the newspaper.

The tainted lamb had been sold in many places, including Henan, Jiangsu and Shanghai, according to?the report.

Gao Yunfang, a food safety authority in Changli county, told the newspaper that so far, the government hadn't found any useful evidence about the production and sales of the banned additive.

Local authorities in the two counties are offering a reward of 20,000 yuan to encourage local residents to report illegal acts related to the banned additive.

A nationwide year-long campaign targeting clenbuterol use in animal husbandry was launched by the State Council, China's Cabinet, in April.

Liang Haoyi, a senior researcher at the China Animal Agriculture Association, said that the government should do more to cut off the supply of such toxic ingredients.

"More attention should be focused on where farmers can buy the toxic additives," he said.