Malaysia on Wednesday charged two women - an Indonesian and a Vietnamese - with murdering the estranged half brother of North Korea's leader in an assassination using a super-toxic nerve agent that killed in minutes.

Siti Aishah, a 25-year-old mother of one from Jakarta, and Doan Thi Huong, 28, from rural northern Vietnam, could be hanged if they are convicted for the killing of Kim Jong Nam at Kuala Lumpur International Airport on February 13.

Police brought the two women to court handcuffed. As they left, they were made to wear bullet-proof vests, reflecting Malaysian authorities' fears that others involved in the killing could want the women silenced.

No plea was recorded after the charges were read out against them.

But, Aishah and Huong have told diplomats who visited them in custody that they were unwitting pawns in an assassination that U.S. officials and South Korean intelligence have said was organised by North Korean agents.

Huong's lawyer told reporters outside the court that his client had told him she was innocent.

"She denied. She denied. She said 'I'm innocent'," Selvam Shanmugam said.

"Of course, she's definitely distressed because she is facing death penalty," he added.

The next court date will be on April 13, when prosecutors will apply for the accused to be tried jointly.

Kim Jong Nam, who had criticised the regime of his family and his half-brother Kim Jong Un, died after the two women allegedly smeared VX nerve agent, a chemical described by the United Nations as a weapon of mass destruction, across his face.

He had been preparing to catch a flight to Macau, the Chinese territory where he had been living under Beijing's protection since going into exile several years ago.

According to the charges the women and four unnamed people, who are still at large, were in the airport departure, with the intention to murder the North Korean citizen.

One North Korean man, identified by police as Ri Jong Chol, is still in police custody and has not been charged yet. Police have identified seven other North Koreans wanted in connection with the case, including an embassy official in Kuala Lumpur.

Amid a bitter diplomatic row, members of Malaysia's cabinet met with a high level North Korean delegation that arrived on Tuesday to press for the release of the citizen in custody, and for the body to be handed over.

Health Minister Subramaniam Sathasivam told reporters he was not at that meeting, but a decision would eventually be made on what to do with the body as no next of kin had come forward for formal identification.

North Korea maintains the victim is a North Korean citizen, but denies he is the half brother of its leader Kim Jong Un.

South Korea's foreign minister told a U.N. sponsored disarmament conference in Geneva on Tuesday that its unpredictable, nuclear-armed neighbour has thousands of tonnes of chemical weapons, including VX.

Yun Byung-se called for "collective measures" against North Korea, including possible suspension of its U.N. membership.

"WASHED HANDS"

Security camera footage, which has been broadcast in the media, showed two women assaulting Kim Jong Nam at the airport around 20 minutes before he died.

Both women have told diplomats from their countries that they had believed they were carrying out a prank for a reality television show. Indonesian diplomats said Aishah told them she was paid around $90 by whoever tricked her into taking part.

Malaysian police have said the suspects had washed their hands after the assault, and were aware that the liquid smeared on their victim's face was toxic.

Aishah's lawyer, Gooi Soon Seng was granted a gag order to restrain police and potential witnesses from making public statements that may incriminate his client.

Police detained Huong 48 hours after the murder in the same airport terminal where Kim Jong Nam was killed. They identified her as the dark-haired woman wearing a white shirt emblazoned with the acronym "LOL", whose image was caught by a security camera while waiting for a taxi after the attack.

Appearing in court on Wednesday, Huong wore a yellow shirt and blue jeans, and her wavy hair was dyed blonde.

Aishah was caught a day after Huong. Police said she suffered a bout of vomiting while in custody that they said was due to side-effects from exposure to the VX. Indonesian diplomats who visited her subsequently said she was in good health.

In court, Aishah indicated that she understood the charges against her. Wearing jeans and a t-shirt, her solemn face framed by long, dark hair, Aishah nodded to Indonesian embassy officials as she left the courtroom.

"We hope that she gets a fair trial, afforded all her legal rights and not tried by the public," Indonesia's foreign ministry spokesman Armanatha Nasir told Reuters in Jakarta.