The pills – a combination of methamphetamine and caffeine – were seized at a roadside checkpoint at 2.30am on Thursday. The driver of a pickup truck, Wiwatchai Chanchoom, was also arrested.

Wiwatchai, 40, allegedly confessed that he was paid Bt50,000 by a woman from northern Thailand to transport the drugs from a spot on the Asia Highway in Phuphin to Nakhon Si Thammarat’s Noppitham district.

Surat Thani police said that with authorities preoccupied helping flood victims, the gang took the opportunity to smuggle drugs.

A separate drug bust yesterday in the Klong Luang district of Pathum Thani saw police seize 10,000 yaba pills from five alleged members of a drug-trafficking gang led by an inmate in the Ratchaburi’s Khao Bin Prison.

The 4am operation, in which alleged drug distributor Yeunyong Larpchotepaisan, 25, was arrested, came after detained drug abusers in the province implicated Yeunyong as their supplier.

Yeunyong allegedly confessed that he took the drugs for distribution to young people in exchange for Bt5,000 per block of pills. The prisoner, identified only as Tong, reportedly gave instructions via phone to a female accomplice.