Using various precursor chemicals, underground labs in Myanmar extract and produce synthetic drugs, such as methamphetamine, which are mainly smuggled into China and Thailand, he said.

To halt the supply of chemicals to Myanmar, police increased their efforts last year against the smuggling of non-pharmaceutical precursor chemicals.

Yunnan province data provided to China Daily showed that 528 tons of non-pharmaceutical precursor chemicals were seized last year, compared with a total of 408 tons seized from 2008 through 2010.

But the task ahead is more difficult than expected, Meng said.

"The types of precursor chemicals that can be used for producing drugs are increasing fast and the underground labs in Myanmar have other sources than China for precursor chemicals."

Yunnan will increase its cooperation with Myanmar and Laos in sharing intelligence and cracking down on drug traffickers and underground labs this year, he said.

But efforts to reduce the domestic demand for synthetic drugs are also important, he added.

According to The Annual Report On Drug Control in China 2011, there were 1.55 million people on mainland taking drugs by the end of 2010. Synthetic drugs were increasingly popular with people younger than 25 as 432,000 of them were taking synthetic drugs.

According to reports, drug dealers now lure youths into trying synthetic drugs, making them believe that synthetic drugs are not addictive and will help them lose weight.

Li Na, director of psychological consultancy at Beijing Tiantanghe Detoxification and Rehabilitation Center, said many young were introduced to synthetic drugs by their friends, and they were more likely to try them when they were depressed, sick or at a party.

Youngsters needs more education about the damage synthetic drugs can do, she added.