The infected individuals are Chinese nationals and close relatives of a 66-year-old man who had tested positive for the disease in Singapore, namely his wife and two grandchildren, whose samples were testing positive, Malaysian Health Minister Dzulkefly Ahmad said.

Dzulkefly explained that information sharing between Singaporean and Malaysian authorities had allowed the individuals to be tracked down.

"Early screening found that they did not have fever and did not have any symptoms of infection. Subsequent clinical samples were taken among these contacts to undergo detection testing and subsequently 2019-nCoV validation at National Public Health Laboratory Sungai Buloh," he said.

The three had been moved from Johor and were currently receiving treatment at the Sungai Buloh hospital in Selangor state, he said.

Malaysian authorities said on Thursday that 8 individuals, including the three confirmed cases, had been placed under quarantine after crossing over to Johor from Singapore.

Dzulkefly said the remaining individuals had tested negative for the virus and had been released, but he added that the development was being taken seriously with authorities keeping a close watch for any developments.

"All health care providers are reminded to pay close attention to the proper use of personal protective equipment (PPE) and to adopt optimal infection prevention and control measures at all times" he said.

"Patient screening at all health facilities should be carried out carefully to ensure that cases that are met will be referred for further investigation."