The government has blocked online portal The Malaysian Insider to "hide the truth", said former prime minister Dr Mahathir Mohamad.

"The government is afraid that people might know the truth. That's why they have to block. It is to safeguard what they are doing. To hide what they are doing.

"They don't allow them to tell the people what is happening in the country," Mahathir told reporters after attending an event at KLCC in Kuala Lumpur today.