Vietnamese Doan Thi Huong is escorted by police as she arrives for court hearing at Shah Alam court house in Shah Alam, outside Kuala Lumpur, Malaysia. Picture: Sadiq Asyraf/AP

Malaysia - The estranged half brother of North Korea's leader had about 1.4 times the lethal dosage of VX nerve agent on his face after he was attacked at a Malaysian airport, a government chemist testified on Tuesday.

Pure VX was found on Kim Jong Nam's face, in his eye and in his blood plasma, Raja Subramaniam, who heads the Center of Chemical Weapons Analysis laboratory, said at the murder trial of two women accused of smearing the chemical weapon on Kim in the brazen assassination in February.

VX and related products were also detected on the clothes both women wore the day of the attack. The trial on Monday had temporarily moved to a high-security laboratory for the judge, attorneys and the defendants to examine the clothing before they were officially accepted as evidence.

Resuming his testimony Tuesday, Raja described the lethal potential of VX. He said animal studies showed the lethal dosage is 0.142 milligrams per kilogram of body weight, and that 50 percent of the tested population will die when exposed to this dosage on their skin.

Raja estimated the concentrate on Kim's facial skin was 0.2 milligram per kilogram of body weight.

Asked if this amount was enough to kill him, Raja said: "I can't give a direct answer on this. Based on concentrate estimate, it is about 1.4 times the lethal dosage."

He said the VX concentrate in Kim's eye was estimated at only 0.03 milligrams per kilogram of his body weight, but that correlated to VX penetrating faster through the eye than through the skin. VX was also found on the collar and sleeves of his blazer, probably because Kim wiped his face on his blazer after the attack, Raja said.

Asked why traces of VX was also detected on fingernail clippings of Vietnamese suspect Doan Thi Huong but not on Indonesian Siti Aisyah, Raja said it was likely that Huong didn't decontaminate herself properly. He said VX can be removed fully by washing and scrubbing the palm within 15 minutes of exposure.

Indonesian Siti Aisyah, centre, is escorted by police as she arrives for court hearing at Shah Alam court house in Shah Alam, outside Kuala Lumpur, Malaysia. Picture: Sadiq Asyraf/AP

Aisyah and Huong pleaded not guilty at the start of the trial last week to murder charges that carry a mandatory death sentence if they are convicted.

Raja's finding of VX on the women's clothing and Huong's fingernails was the first evidence linking VX to the two suspects. Their attorneys have said the women were duped by suspected North Korean agents into believing they were playing a harmless prank for a hidden camera TV show.

Under cross-examination, Raja said it wasn't possible that the VX used to kill Kim was a "binary" concoction of two non-fatal elements as high temperature would be required to create VX.

He agreed with the defense's assertion that actual VX could have been smuggled into Malaysia or a non-fatal compound could have been smuggled into the country and mixed with sulphur, another non-toxic element, to create VX in a clandestine laboratory.

Raja also said he discarded samples of clothing that were cut and tested for VX under the standard operating procedure recommended by the Organization of Prohibition of Chemical Weapons. The defense lawyer had questioned why the samples were not kept for verification by the court.

He also said his findings identifying VX and detecting it on the various items admitted as evidence were not sent to laboratories abroad for verification.

Prosecutors have said they will present airport security videos this week that show the two women carrying out the attack and indicate they knew they were handling poison.

"We have an uphill battle in this case. We are the underdogs. They have the upper hand but we have our own strategy," prosecutor Wan Shaharuddin Wan Ladin told reporters later.

VX is banned by an international treaty as a weapon of mass destruction but is believed to be part of North Korea's chemical weapons arsenal.

Kim was the eldest son in the current generation of North Korea's dynastic rulers but lived in virtual exile as an apparent family outcast. North Korea experts say he may have been killed because he was perceived as a threat to the nation's current leader, Kim Jong Un.

An airport security video reviewed by The Associated Press on Monday shows what may be Kim's final recorded moments of life after he fell perilously ill at the Kuala Lumpur airport on February 13. The video shows Kim apparently unconscious on a gurney and being given oxygen by medical attendants waiting for an elevator to take him to an ambulance.

The scene in the video appears almost casual, in contrast to the dramatic news of his death once it was made public.

The video was first broadcast late Sunday by Japan's Fuji TV.

In these images made from February 13, 2017, video provided by Fuji TV, Kim Jong Nam, half-brother of North Korean leader Kim Jong Un, is stretchered at Kuala Lumpur International Airport in Sepang, Malaysia.  Picture: Fuji TV via AP

Picture: Fuji TV via AP

AP