The Malaysian Communications and Multimedia Commission (MCMC) and police are investigating a report that the private data belonging to millions of Malaysian are being sold online.

"As a preventive measure, MCMC has asked the administrators of Lowyat.net to take down the said advertisement.

"The administrators have cooperated and taken down the advertisement and the related article.

"The MCMC urges the public not to speculate until the authorities have completed their investigations," MCMC said in a statement today.

Lowyat.net yesterday reported that personal data, including 50 million entries from various telcos, were being sold online.

It said the data included customer names, billing addresses, mobile phone numbers, SIM card numbers and MyKad numbers of customers.

It added the data breach was believed to have occurred between 2012 and 2015.

Other data being sold included names, login IDs, hashed passwords, email addresses, nationalities, addresses and mobile phone numbers from job advertisement websites, as well as the personal data of doctors.