An Indonesian woman held for two years on suspicion of killing North Korean leader Kim Jong-un’s half-brother is free from custody after a Malaysian judge discharged the murder charge against her.

The judge discharged Siti Aisyah after prosecutors said they wanted to withdraw the charge. They did not give a reason.

Ms Aisyah was quickly ushered out of the courtroom and into a waiting car, telling reporters she had only learned Monday morning that she would be freed.

“I am surprised and very happy,” Ms Aisyah said.

The murder trial of Vietnamese Doan Thi Huong was put on hold after the surprise development. She was to have begun giving her defence in Monday’s court session, after months of delay.

Vietnamese woman Doan Thi Huong was also accused of the assassination, but her trial has now been put on hold. Photo: AAP

Indonesian Ambassador Rusdi Kirana said he was thankful to the Malaysian government.

The two young women were accused of smearing VX nerve agent on Kim’s face in an airport terminal in Kuala Lumpur in February of 2017.

The pair have said they thought they were taking part in a prank for a TV show.

They were the only suspects in custody after four North Korean suspects fled the country on the morning Kim was killed.

Salim Bashir, a lawyer for Huong, said previously she was prepared to testify under oath for her defence.

“She is confident and ready to give her version of the story. It is completely different from what the prosecutors had painted. She was filming a prank and had no intention to kill or injure anyone,” he told the Associated Press.

Kim Jong-nam was the older half-brother of North Korean leader Kim Jong-un. Photo: AAP

Lawyers for the women have previously said they were pawns in a political assassination with clear links to the North Korean embassy in Kuala Lumpur, and that the prosecution failed to show the women had any intention to kill. Intent to kill is crucial to a murder charge under Malaysian law.

Malaysian officials have never officially accused North Korea and have made it clear they don’t want the trial politicised.

Kim Jong-nam was the eldest son in the current generation of North Korea’s ruling family. He had been living abroad for years but could have been seen as a threat to North Korean leader Kim Jong-un’s rule.

Murder carries a mandatory sentence of hanging, but Malaysia’s government plans to abolish the death penalty and has put all executions on hold until the laws are changed.