China's top quality watchdog said late Friday that Chinese importers purchasing dairy products from New Zealand company Fonterra should immediately initiate recalls of potentially contaminated products, according to a press release on its website on Saturday.

Fonterra said Friday that some whey protein produced in May 2012 was found with clostridium botulinum, which can cause botulism.

China's General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ) has demanded the New Zealand side to act immediately to prevent the tainted products from harming the health of Chinese consumers.

AQSIQ has told quality agencies nationwide to strengthen inspection over milk products from New Zealand.