The Central Drugs Standard Control Organisation's directive also said laboratories should issue test reports immediately, or as early as possible, after analysing samples from manufacturers.
India made tests for cough-syrup exports mandatory earlier this week after the World Health Organization (WHO) found toxins in cough syrups made by three Indian companies.
Syrups made by two of these companies were linked to the deaths of 70 children in Gambia and 19 in Uzbekistan last year.
The deaths shook the reputation of India's $41bn pharmaceutical industry, one of the world's largest, and the government is considering an overhaul of its pharmaceutical industry policy to tighten procedures on testing and raw materials.
The directive was sent to all federal government laboratories and to drug regulators in six major production states and one federal territory.
From 1 June, all cough syrup exported from India will need a certificate of analysis from a government laboratory. The health ministry has not responded to requests for comment from journalists on whether such tests would also be required for the domestic market.
Indian tests of cough syrups made by Maiden Pharmaceuticals Ltd, linked to the deaths of children in Gambia, found no toxins but contaminants were detected in many drugs made by Marion Biotech, whose syrups were linked to deaths in Uzbekistan. The companies deny any wrongdoing.
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