Public Health Minister Cholnan Srikaew has signed proposed legislation regarding cannabis, emphasising that it cannot be used for recreational purposes.

"The new law will clearly stipulate that cannabis must be used for medical purposes only. It will also encourage the use of cannabis for a range of health benefits," Dr Cholnan said on Saturday.

"Regarding the using of cannabis for recreational purposes, there will be a clear measure to control and prevent this.

"The measure may come in the form of a ministerial regulation passed by the cabinet, or from a panel," he said.

If the cabinet approves the principle of the bill, it will be submitted to the Lower House for consideration.

"Whether the buying of cannabis will require a medical certificate or not has not been included in the bill just yet," he said.

Asked about cannabis stores, Dr Cholnan said there have been no laws set to revoke licences for running legally-registered stores. But once the law is put in place, cannabis stores must sell only the parts of the cannabis plant that are deemed legal in Thailand.

Under the Narcotics Code, only products containing over 0.2% THC [tetrahydrocannabinol -- cannabis' main psychoactive agent] by weight will be considered illegal.