Ministry of Agriculture and Rural Development has said the melamine content in animal and fish feed should not be above 2.5 milligrams per kilogram.
It said the new regulation is based on standards prevailing in places like the US, Canada, and the EU.
The ministry has also strictly forbidden import and use of melamine for producing animal feed.
Deputy Minister of Agriculture and Rural Development Luong Le Phuong said all animal feed found to contain melamine had been destroyed last month. Inspectors are continuing to check animal feed producing units.
Shipments of animal feed coming into Vietnam would have to have certificates of origin, he said.