Agents uncovered the drugs early Monday after they boarded the Hung Chi Yu No 7, a fishing boat, in the Bashi Channel between Taiwan and the Philippines, according to a spokesman from the Bureau of Investigation.

"With the help of US-based high-tech satellite technology, we had been able to monitor the vessel from the moment it left Cambodia," the spokesman said.

He said it was the largest heroin smuggling case uncovered by the bureau since 2002 when it confiscated 120 kilograms.

Agents arrested two people on the fishing boat, and later detained five others suspected of involvement, including a low-ranking politician from a township in southern Taiwan.

The spokesman declined to specify the street value of the heroin, believed to be intended for local Taiwanese use, but media on the island put the estimated price at Tw$2.4 billion ($80 million).

Under Taiwan's stern anti-drug laws, the suspects could be sentenced to death if convicted.