Minister of Agriculture and Rural Development Cao Duc Phat has called for increased publicity concerning the use of steroids used to produce unnaturally heavy pigs so that residents shun the hazardous meat.
"This is an evil crime and not simply a violation of law," the Nguoi Lao Dong Newspaper quoted him as saying.
An investigation by Thanh Nien found that the use of Î²- agonist growth-promoting hormones to raise swine was widespread.
Popular forms of the agent are clenbuterol and salbutamol, which were designed to treat asthma and lung conditions, but only under strict supervision.
The drug can raise the heart rate and blood pressure, causing digestive disorders and various other diseases.
Nguyen Xuan Duong, deputy head of the Husbandry Department at Vietnam's Ministry of Agriculture and Rural Development said eating pork containing the agent could lead to neurological problems and cancer.
A recent survey by Duong's agency found a significant proportion of pork contained the dangerous chemicals.
Up to 43 percent of pig urine and 24 percent of pork taken from many slaughterhouses in Ho Chi Minh City had the Î²- agonist, the agency found.
Minister Phat said the situation was "alarming" and the use of illegal chemicals in husbandry must be taken as seriously as other drug offences.
According to Nguoi Lao Dong, the illegal chemicals have been extensively used by up to half of farmers in Dong Nai Province. The proportion is between 20-25 percent in Ba Ria Vung Tau, 10 percent in Binh Duong and 5 percent in Tay Ninh.
A pig trader in Dong Nai said the illegal chemicals arrive from China packed into unlabeled parcels between 20-50 kilograms. Smuggling them into Vietnam has involved hiding the product among agriculture powders and other legal entities, he said.
Nguyen Tri Cong, chairman of Dong Nai Husbandry Association, said his agency has coordinated with related ones to inspect for the use of the chemicals and has been threatened by many pig traders.
"They warned us to restrain our inspections or risk being killed," he said.
Duong of the husbandry department said according to the Penal Code, farmers who use the illegal chemicals may be imprisoned for three to five years. They also face fines between VND10-50 million (US$480-2,400).
"Legal penalties exist. The question is whether local authorities will be sufficiently determined to enforce the regulations," he said.
According to Duong, the agriculture ministry will coordinate with the Ministry of Public Security, the Health Ministry and relevant agencies to conduct more inspections against illegal distribution and use of the chemicals.