Thailand's decriminalization of cannabis has delighted its fans, alarmed some health experts and has increasingly disappointed farmers who have been undercut by illegal imports, sending a promise of a new bonanza crop up in smoke.

Marijuana has also become an election football with the opposition criticizing the ruling pro-military coalition in the run-up to May 14 polls for rushing through decriminalization last year to what they say is the detriment of society, youngsters in particular.

Thousands of cannabis shops and businesses have sprung up — especially in Bangkok and other tourist spots — since Thailand became the first Southeast Asian country to decriminalize the drug.