Indonesian Siti Aisyah and Vietnamese Doan Thi Huong, who arrived at the heavily guarded court in handcuffs and wearing bulletproof vests, entered their pleas through interpreters as proceedings got under way.
The defendants were arrested just days after the killing of Kim Jong-Nam on February 13 as he waited to board a plane to Macau at Kuala Lumpur airport.
The women are accused of rubbing toxic VX nerve agent, a chemical so deadly it is listed as a weapon of mass destruction, on his face.
Kim died an agonising death about 20 minutes after the hit, which was caught on airport CCTV as the VX rapidly shut down his central nervous system.
The defendants -- who face the death penalty if convicted -- claim they were duped into believing they were taking part in a prank for a reality TV show.
The murder sparked an angry row between North Korea and Malaysia with both countries expelling each other's ambassadors.
The women were led into Sham Alam High Court, outside Kuala Lumpur, in handcuffs for the start of the trial. Aisyah, 25, was wearing traditional Malaysian dress and Huong, 29, a blue jumper.
The murder charge was read to them in their native languages and interpreters assigned to the defendants indicated they were pleading not guilty.
Prosecutor Muhamad Iskandar Ahmad then read a statement giving details of the murder and said the prosecution had sufficient evidence to prove the women's guilt.
"We will provide evidence that the dead victim was at (Kuala Lumpur International Airport) departure lounge when Siti Aisyah and Doan Thi Huong approached the dead victim and swiped a poisoned liquid on the face and eyes of the victim," he told the court.
"The evidence clearly showed that their action to swipe the poison known as VX caused the death of the victim. Expert evidence will be shown that the VX was the cause of death and the chances to save him were extremely slim."
He said the women had carried out exercises with four other people before the murder to ensure they succeeded in their "common intention" of killing Kim.
- Murder mystery -
Defence lawyers immediately demanded the court reveal the names of four other people charged over the murder.
The four were formally accused in March of the assassination alongside Aisyah and Huong but authorities said they were still at large and have not disclosed their names.
Police have said four North Korean suspects fled Malaysia on the day of the murder, and the women's defence teams insist these individuals are the main suspects.
About 200 police officers had been deployed to guard the court. The defendants arrived in a convoy of police cars with their sirens blaring.
The trial could at last shed light on the many unanswered questions surrounding the murder.
These range from how two women living precarious existences among Malaysia's army of migrant workers allegedly became involved in a high-profile assassination, to how a lethal nerve agent was deployed in an airport and killed Kim but harmed no one else.
South Korea accuses the North of being behind the murder of Kim Jong-Un's estranged half-brother, who had voiced criticism of the regime after falling from grace and going to live in exile overseas.
The North denies the allegation.
The run-up to the trial has been marked by fierce criticism from the women's lawyers who say the accused are the fall guys in the case.
As well as the North Koreans who fled immediately after the assassination, several others allegedly linked to the murder plot were allowed to leave the country later to ease the diplomatic crisis.
The women's legal teams also accuse prosecutors of dragging their heels on handing over key material required to mount a defence.
Prosecutors -- who insist the women will get a fair trial -- will lay out their case over two months and call 30 to 40 witnesses. The defence is then likely to be called.
Prior to the murder, Malaysia had been one of Pyongyang's few allies amid a global outcry over the country's atomic weapons programme.
After the assassination sent diplomatic relations plummeting between Pyongyang and Kuala Lumpur, tensions only eased when Malaysia agreed to return Kim's body in March.
Published : October 02, 2017
By : Agence France-Presse