Bentong police spokesman said when contacted that the accident occurred at about 8am.
Efforts were underway to extricate two passengers still trapped in the bus, according to a Fire and Rescue Department spokesman.
He added that three fire engines and 25 rescue personnel were at the accident site.
Police said the bus was on its way back from Genting Highlands when it went out of control and skidded while negotiating a sharp downhill bend at about 8am.
“It hit the road divider and overturned,” Bentong police spokesman told Bernama.
The victims — a man and a woman — died on the spot, he said. Police are establishing their identity.
The injured as well as the two bodies have been brought to Kuala Lumpur Hospital.
Police have detained the bus driver and its attendance.