Only a small amount of nerve agent -- but more than enough to kill him -- was found on the face of the North Korean leader's half-brother after he died in agony following an airport attack, a court heard Tuesday.

Kim Jong-Nam had 0.2 milligrams of VX per kilogram of body weight on his facial skin, well above the typical lethal dosage, chemist Raja Subramaniam told the trial of two women accused of his murder.

VX is so deadly it is listed by the United Nations as a weapon of mass destruction, and Kim died shortly after the attack as it overcame his nervous system.

Indonesian Siti Aisyah and Vietnamese Doan Thi Huong, in their 20s, are accused of smearing the poison on Kim's face in February at Kuala Lumpur International Airport in a hit that stunned the world.

The women, who were arrested a few days after the killing and face death by hanging if convicted, have pleaded not guilty to murdering the estranged half-brother of Kim Jong-Un as he waited to board a flight to Macau.

On Tuesday Raja outlined to the Shah Alam High Court near Kuala Lumpur how much VX was found on Kim's face. 

Asked if it was enough to kill, he responded: "I can't give a direct answer to this. Based on concentration estimate, it is about 1.4 times the lethal dosage."

He said that VX was also found on the collar of Kim's blazer and its sleeves, which he likely used to wipe his face after the attack.

Raja previously testified that VX was found on the defendants' clothing, the first evidence linking them directly to the poison.

On Monday the trial visited a high-security laboratory to examine the poison-tainted clothes worn by the women on the day of the attack. 

The defendants say they were duped into believing they were taking part in a prank for a reality TV show, and their lawyers blame North Korean agents for the assassination.

The murder sparked a fierce row between Malaysia and North Korea, which is suspected of ordering the hit. Pyongyang denies the allegation.