At least 10 people were killed when a private jet crashed onto a car and a motorbike on a highway as it attempted to land, Malaysian police say.

Malaysia's civil aviation authority said six passengers and two crew had been on board the Beechcraft jet.

The jet had been travelling from Langkawi to Selangor, to the west of the capital Kuala Lumpur.

The Selangor police chief said the aircraft had lost contact with the air traffic control tower.

"There was no emergency call, the aircraft had been given clearance to land," Hussein Omar Khan said.

Investigators are trying to find the plane's black box containing its flight data.

"For now we cannot say what was the cause of the crash since investigations are underway," Transport Minister Anthony Loke said.

"Forensic officials are identifying the remains of all the victims," he added.

A witness told Reuters that he had been working on-site as an engineer when he heard an explosion. He went to where the crash happened and saw injured people.

Mohamad Syahmie Mohamad Hashim, a former member of the Malaysian Air Force, told AFP that he saw the plane flying erratically.

"Not long after that I heard a loud boom," he said. "I sped towards the location and saw the remains of an aircraft. I couldn't do anything."