A cause of death has not yet been determined for the half-brother of North Korea's leader who died last week after apparently being poisoned in the budget terminal of a Kuala Lumpur airport, Malaysian officials said.

Noor Hisham Abdullah, the country's director general of health, told reporters the post mortem showed no evidence of a heart attack in Kim Jong Nam's death, or any sign of puncture wounds on his body.

Medical specimens have been forwarded to experts, who will determine the cause of death of the half-brother of North Korea's leader Kim Jong Un.

"We have to confirm with the lab report before we can make any conclusive remark," said the director general of health.