Nguyen Ngoc Quang, deputy head of the anti-drug police department, said the new method is why members of the public and authorities have frequently been finding drugs, mostly cocaine, washing up on beaches in central and southern Vietnam for months now.
Just six days ago authorities found 28 kg of drugs floating off Go Cong beach in Kien Giang.
A further search netted another 24 kg.
In January around 300 packets of drugs were found drifting ashore in Quang Ngai.
Many people who find drugs hand them over to authorities, but some keep them either due to ignorance or greed, Quang said.
People should report to authorities whenever they find drugs, he added.
Drugs are also transported through ports hidden in cargo.
Criminals use boats masquerading as fishing vessels to support their accomplices and evade authorities.
The use of GPS trackers to transport drugs by tossing them in the sea is a method seen in several countries around the world.
In July last year Irish police seized two bags of cocaine weighing 30 kg that washed up on Donegal beach.
Authorities said criminals had attached the bags to a buoy with a tracker, waiting for a vessel to come and pick them up.
Currents or winds possibly snapped the ropes attaching the drug bags to the buoy, causing them to float loose.