BANGKOK (REUTERS) - Thai anti-narcotics officers have seized 176kg of crystal methamphetamine hidden in the metal frames of electric treadmills bound for Japan, police said on Thursday (Nov 14).

"Last month, the Australian police busted a similar case with the drugs hidden in exercise equipment, which they told us was packaged and exported from Thailand," Police Major-General Yingyot Thepchamnong, head of the Narcotics Suppression Bureau told Reuters. "So, we followed up in the belief there must be other cases."

He said officers at Bangkok's Suvarnabhumi airport on Tuesday discovered 36kg of crystal meth stashed in exercise equipment among air cargo bound for Japan, enabling them to track the shipment back to the warehouse.

During the raid on the warehouse, police found a further 140kg inside the frames of 10 treadmills.

One person was arrested following the raid, though Maj-Gen Yingyot said police believe more suspects were involved.

Thailand is a major trafficking route for crystal meth manufactured in Myanmar's Shan and Kachin states. The meth market has expanded at an alarming rate as drug seizures have surged more than tenfold over the past two years, official statistics show.

The United Nations Office on Drugs and Crime estimates that the Asia-Pacific methamphetamine trade alone was worth as much as US$61.4 billion (S$83.7 billion) in 2018, up from an estimated US$15 billion just five years earlier.