An Australian diplomat in Thailand has reported an incident involving young Australians who were drugged, raped and robbed while partying on beaches. They were allegedly given drugged cocktail drinks made from native leaves potentially slipped by criminals who plan to take advantage of the situation.

The drug known as "kratom" is often combined with the DEET insect repellent along with soda, ice and cough medicine. The deadly cocktail drink will leave unsuspecting targets in a vulnerable and weakened state, according to Larry Cunningham, an Australian honorary consul based in Phuket, Thailand.

Thailand is known for its beach rave parties usually flocked with tourists together with the locals. Those who become victims of rape and robbery often fail to report crimes to the local authorities. The extent of the crimes committed using drugged cocktails remains relatively unknown.

Kratom is a type of tree from the coffee family that is commonly found in Southeast Asian jungles. Its effect is similar to opium. Its low cost has led unscrupulous individuals to use it in tourist areas. Twenty leaves of kratom will be enough to create a drugged cocktail for several people.

Kratom was declared illegal in Thailand since 1943 but Justice Minister Chaikasern Nitsiri has proposed to legalise the drug. He said kratom could deter people from using deadlier drugs like crystal meth and methamphetamine.

Mr Nitsiri told reporters in a press conference that kratom was originally used as part of traditional medicine in the past.

In an interview on the night of his retirement as an Australian diplomat, Mr Cunningham said Australian parents would be alarmed how Thai criminals prey on young foreigners like Australians. Beach parties like those often held in Koh Phangan, an island where 30,000 party goers jostle space in a kilometer of the beach, ravers usually drink cocktails from buckets.

Mr Cunningham said some of the worst criminals in Thailand can be found in beach rave parties. One Australian woman showed up in the embassy of Australia in Bangkok wearing only her bikini and a shirt. She said she was gang-raped and robbed of her valuables during a beach party. She said someone had placed her inside a bus going to Bangkok.

Mr Cunningham has advised people to stay away from Thai beach parties. He said even tourist groups are not safe from criminals.