A 44-year-old Thai man was arrested Thursday after 158 kg of methamphetamine were seized from treadmills bound for Japan, according to Thai authorities.

Police called it the largest single seizure of "ice," as the drug is known, headed for Japan.

A tipoff led the Central Narcotics Bureau on Tuesday to a consignment of two treadmills at a shipping company. Sending such heavy and bulky exercise equipment via costly air freight to Japan raised suspicions, and a search of the consignment found packets of the drug concealed within the steel tubing.

The police subsequently found 10 other treadmills similarly stuffed with meth at a Bangkok warehouse rented by the Thai man. The drugs have a street value of about $89 million (about ¥9.66 billion).

The man was arrested on suspicion of attempting to export illicit drugs. He denied the charges.

The smuggling of stimulants to Japan appears to be on the rise. The Thai police announced Wednesday they had seized about 8 kg of meth hidden in two wall clocks that were to be shipped to Osaka.