All New Zealand milk powder exported to Sri Lanka must now be tested in approved laboratories for dicyandiamide residue before it can be sent.
Dicyandiamide is the chemical detected in New Zealand milk late last year from the nitrification inhibitor products some farmers applied to their pastures.
The Ministry for Primary Industries says Sri Lanka insists on the testing while it evaluates the risk DCD poses to its people.
Deputy director-general Carol Barnao said exporters must supply the ministry with evidence the testing has been conducted before it will issue the health certificate that is needed to export.
She said New Zealand continues to work with Sri Lanka to provide assurances about the safety of New Zealand milk.
Sri Lankan officials have repeatedly questioned the official New Zealand Government line that DCD is safe for people to consume at low levels.
They have also alleged that New Zealand milk has been found to be radioactive.
Last week, Foreign Affairs Minister Murray McCully met Sri Lankan government officials and spoke about the dairy trade between the countries.