Online commentator Raja Petra Raja Kamarudin has increasingly infuriated authorities by publishing numerous claims about alleged wrongdoings by government leaders on his popular site, Malaysia Today.
The government has denounced most of Raja Petra's allegations as lies.
Raja Petra's wife, Marina Lee Abdullah, said police came to their home on Friday to serve an arrest warrant on him.
Mdm Marina said police informed them he was being arrested under the Internal Security Act, a widely criticised law used against suspects regarded as national security threats.
Government and police officials could not immediately be contacted. -- AP