An Australian man allegedly carrying meth concealed in soap bars has been arrested as he prepared to board a flight to Perth.

The 68-year-old was taken into custody before he reached the departure gate at Suvarnabhumi Airport in Bangkok, Thailand on Sunday.

WATCH THE VIDEO ABOVE: Australian arrested in Thailand allegedly carrying kilos of meth.

Know the news with the 7NEWS app: Download today

Authorities allege he was attempting to smuggle more than four kilograms of meth back to his home country.

The haul was allegedly found hidden in bars of soap, in a bag, and in a hidden suitcase compartment.

Customs spokesman Panthong Loikulnan said the Australian had been flagged through intelligence as a high-risk traveller, and was nabbed before he could leave via Thailand’s major international gateway.

The Southeast Asian country has strict penalties for drug trafficking, including the death penalty.

Loikulnan said authorities had made it a priority to crack down on the trade of drugs and illegal goods.

Since October, customs workers at the airport have made close to 200 drug seizures involving heroin, cocaine and meth.

Australia’s Department of Foreign Affairs and Trade said it is providing consular assistance to an Australian man detained in Thailand.

The department would not expand further but it is understood consular assistance may include visits to prisons to monitor welfare, checking in with local authorities regarding the Australian’s well-being, and helping them communicate with family.