Vietnam's agriculture ministry has ordered an exhaustive investigation into allegations that some back tea shipments to Taiwan were contaminated with the highly toxic compound dioxin.
Minister Cao Duc Phat asked inspectors to report on the origin of the batches which Taiwanese authorities claimed to be tainted.
He asked local authorities to find out if the tea was really contaminated with dioxin and at what stage of production. The production process needs to be reviewed to regain the reputation of local exporters, he said.
Earlier in April, Taiwan's authorities warned that seven batches of black tea imported from Vietnam were contaminated with dioxin, one of the most toxic compounds ever known.
They also warned that 22 other batches exceeded the allowed pesticide residue limit.
According to Taiwanese data, 70 percent of its black tea imports are from Vietnam. However, a survey in 2014 showed that 17 percent of the Vietnamese tea did not meet Taiwan's standards.
In November, around 200 tons of tea grown in the Central Highlands province of Lam Dong was able to clear customs in Taiwan, after being held for months over dioxin contamination rumors.