Hishamuddin said there was no sign of any plane wreckage and denied Vietnamese state media reports that the plane had crashed south of an island off Vietnam.
"We are doing everything in our power to locate the plane. We are doing everything we can to ensure every possible angle has been addressed," Hishamuddin told reporters near the Kuala Lumpur International Airport.
"We are looking for accurate information from the Malaysian military. They are waiting for information from the Vietnamese side."