Stored in a Binh Chanh District warehouse, police discovered the stash on November 3, Pham Van Cac, chief of drug related crime at the Ministry of Public Security, said on Thursday. The drugs were about to be shipped overseas, said Cac, highlighting the arrest of suspects Ha Tan Ban, 39, and Tran Van Duc, 40.

The discovery was part of an ongoing investigation started in March, which previously saw the arrest of several Lao, Taiwnese and Vietnamese nationals alongside the seizure of about 300 kgs of heroin.

The ring is helmed by a group of Taiwanese men, 66-year-old Yu Chi Phu and 32-year-old Yen Yung Chu, said Cac. Two ring members, Taiwanese Yang Po Hung and Yang Kai Chen, Phu's underlings, were arrested in October in Taiwan thanks to collaboration between Vietnam and Taiwan police.

The ring hid drugs in containers shipped from Cambodia to Vietnam and then Taiwan, authorities found. Hung and Chen hired Vietnamese to rent five locations in the outlying Binh Chanh as hideouts. The ring masqueraded their criminal activities as logistical activities, authorities said.

"By the end of our investigation, Vietnam and Taiwan had seized a total of 461 kgs of heroin. It is the largest amount of drugs the Ministry of Public Security has ever handled," said Cac.

Vietnam has become a key trafficking hub for narcotics around the Golden Triangle, an intersection of China, Laos, Thailand, and Myanmar and one of the world’s largest drug producing regions.

It also has some of the world’s toughest drug laws. Those convicted of possessing or smuggling more than 600 grams of heroin or more than 2.5 kilograms of methamphetamine face the death penalty.