Surveillance video showing the apparent moment North Korean leader Kim Jong-un's estranged half-brother was fatally attacked at Kuala Lumpur airport has emerged.

Kim Jong-nam, the eldest son of previous leader Kim Jong-il, died last week after apparently being poisoned.

The grainy security camera footage, obtained by Fuji TV, appears to show two women approach Kim from different directions as he stands at a ticket booth in the airport.

One of the women comes up behind him and appears to hold something over his mouth for a few seconds.

The women then turn and walk off in different directions.

Kim is later seen seeking out help from airport staff and security officials, before being led to an airport clinic.

He is filmed being put on a stretcher. He died minutes later.

The two women seen in the surveillance footage are allegedly among four people arrested in relation to Kim's death, with two men also held.

Kim Jong-nam, left, was estranged from his younger brother, North Korean leader Kim Jong-un. Credit: AP

The results of a post-mortem into the death are yet to be published as a diplomatic row between Pyongyang and Malaysia continues to escalate.

North Korea's top envoy in Kuala Lumpur denounced Malaysia's investigation into the apparent assassination, calling it politically motivated and demanding a joint probe into the death.

Malaysia recalled its ambassador to Pyongyang over what it called "baseless" allegations.