An Australian tourist was arrested for allegedly trying to smuggle 22 kilos of meth through an airport in Thailand.

Tran Huybao Khang, 28, was reportedly caught with the drugs while trying to board a plane at the Suvarnabhumi International Airport in Bangkok on May 18.

Staff flagged his belongings after finding 'density abnormalities' in his luggage during inspections. They said they rifled through the bags and discovered the plastic packs of methamphetamine inside.

Authorities said Tran, of Vietnamese and Australian descent, was due to fly to Melbourne on Thai Airways flight TG461, an Airbus A350, before his arrest.

Phanthong Loykunlanan, spokesman of the Customs Department, said: 'The owner of the bag was an Australian passenger who was trying to take the crystal meth to Australia, where its value would increase tenfold.

'We believe the suspect was not selling the drugs himself. In previous cases, the tourists we arrested were just couriers delivering the drugs to a drugs network in the country of destination. They may have been in debt or were hired, but they are not the sellers themselves.

'As for where the drugs came from, we cannot say because the case is under investigation.'

Meth is classified as a category 1 substance in Thailand.

Under Thai law, using category 1 substances may be punished with up to three years in jail and a fine of up to 60,000 baht, while possession carries a fine of up to 200,000 baht and up to 10 years imprisonment.

Those convicted of dealing may face life imprisonment and a five million baht fine, depending on the amount involved. Producers, importers, and exporters of Category 1 substances face the same charges and may face the death penalty if it is proven their intent was to sell or distribute on a large scale.