BANGKOK (Reuters) - Dozens of Thai cannabis advocates urged the government on Thursday to abandon its plans to re-list marijuana as an illegal narcotic, a week after it announced its dramatic policy U-turn just two years after de-criminalising it.

Thai Prime Minister Srettha Thavisin has made a push to allow cannabis use only for medical purposes, promising a tough stand on illicit drugs that he said were causing addiction and destroying the future of young people.

Pro-cannabis groups met the health minister on Thursday and urged him to rethink the policy reversal.

"Even as medical use, don't bring the people's plant into the system. It has been our recipe for hundreds of years. When you need licenses there is corruption," said Prasitchai Nunual, secretary-general of Thailand's Cannabis Future Network.

Thailand first legalised cannabis for research and medical use in 2018 and two years ago removed the plant from the national narcotics list, allowing people to grow, sell and consume cannabis.

That led to an explosion of recreational use, with thousands of cannabis cafes and dispensaries popping up nationwide, especially in tourist hotspots, in an industry projected to be worth up to $1.2 billion by 2025.

Critics say liberalisation was rushed by the previous government, with no cannabis bill drafted or clear rules in place in Thailand, causing widespread public confusion and misuse.

Thailand has a long tradition of using marijuana to relieve pain and fatigue, with use also in traditional medicine and recipes. Public Health Minister Somsak Thapsutin told the group cannabis should be used only for medical purposes.

But many cannabis businesses say the problem is not recreational use of cannabis, but the haze surrounding rules or regulations.

"There is nothing more reasonable than a comprehensive Cannabis Act, which already addresses the safety concerns like use among children and controlled growth," activist and cannabis retailer Chokwan Chopaka said.

"We do not support a wild west of marijuana in Thailand, but policy that backs farmers, retailers and medical users."

(Reporting by Chayut Setboonsarng and Panarat Thepgumpanat; Editing by Martin Petty)