The two women accused of killing the North Korean leader's half brother have toured the Malaysian airport where the attack took place as part of their trial.

The judge, prosecutors, defence lawyers and representatives of the women's home countries were escorted inside the Kuala Lumpur airport by heavily armed police on a visit meant to give the trial participants a better perspective of events as they unfolded.

Indonesian Siti Aisyah and Doan Thi Huong of Vietnam appeared subdued as the group moved around. The women, who have pleaded not guilty, were handcuffed and wearing bulletproof vests as they have often since their arrests.

High Court Judge Azmi Ariffin visited the check-in kiosk in the budget terminal where the two women alleged smeared VX nerve agent on to Kim Jong Nam's face on February 13.

The judge followed the path Mr Kim walked to the airport clinic, seeking help after being attacked, and retraced the movement of the two women, who were seen on security footage rushing to restrooms afterwards to wash their hands.

Mr 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.

He was not thought to be seeking influence over his younger brother Kim Jong Un but had spoken out publicly against his family's dynastic rule.

Huong and Aisyah are the only two suspects detained in the case.

Their defence lawyers have said the women were duped by suspected North Korean agents into believing they were playing a harmless prank for a TV show.

Since the trial opened on October 2, witnesses have testified that Mr Kim died from acute VX poisoning and that the banned chemical agent was found on his face and clothing and on the women's clothing and on Huong's fingernail clippings.