Two women – an Indonesian and a Vietnamese – will be charged with murder on Wednesday over their alleged involvement in the killing of the estranged half brother of North Korea's leader at Kuala Lumpur's main airport, Malaysia's attorney general said.

Police have said that the women smeared VX nerve agent, a chemical on a UN list of weapons of mass destruction, on Kim Jong Nam's face in an assault recorded on airport security cameras on February 13.

U.S. and South Korean officials believe Kim Jong Nam was the victim of an assassination orchestrated by North Korea. He had criticised the regime of his family and his half brother Kim Jong Un in the past and had been living in exile, under Beijing's protection, in the Chinese territory of Macau.

While Malaysian police arrested Doan Thi Huong, the Vietnamese, and Indonesian Siti Aishah in the days after the attack, they are are also holding one North Korean man and have identified seven other North Koreans wanted in connection with the sensational case.

Attorney general Mohamed Apandi Ali said the North Korean in custody will not be charged yet. His detention period ends on Friday.

The security camera footage, which has been released in the media, showed two women assaulting Kim Jong Nam in the departure hall of Kuala Lumpur International Airport, and the victim stumbling into a medical clinic. He died within 20 minutes of the assault.

Footage shows moment of Kim Jong-nam assassination

Both women have told diplomats from their countries that they had been paid to take part in what they believed was a prank for a reality TV show.

The attorney general said the women will be formally charged on Wednesday under section 302 of the penal code, which carries the death penalty.

"I can confirm that," he told Reuters in a text message.