The women went on trial, but in March prosecutors dropped the murder charge against Aisyah after diplomatic pressure and she flew home.

Then last month they withdrew murder charges against Huong, who pleaded guilty to a reduced count of "causing injury" and was told she would be released in May at the end of her sentence.

More than two years after her arrest, the 30-year-old former hair salon worker was freed from prison outside the Malaysian capital at about 7:20 am (2320 GMT Thursday), her lawyer Hisyam Teh Poh Teik told AFP.

Journalists waiting outside the jail saw a van and a car with tinted windows race past, and a court official at the scene also confirmed Huong had been released.

She was expected to head to an immigration office in administrative capital Putrajaya to sort out documentation, before flying to Vietnam in the evening.

- 'True killers escaped justice' -

While there is relief for the women, no one else is in custody over the murder and those behind the plot are unlikely to ever be punished.

"The assassins have not been brought to justice," said Hisyam, adding the women's legal teams consistently argued that four North Koreans who fled Malaysia after the killing, and were charged in absentia, were the real murderers.

The women were arrested after they were captured on airport CCTV cameras walking up behind Kim as he waited for a flight, and one was seen clasping her hands over his face.

Kim, who fell from grace in the North after a bizarre attempt to visit Tokyo Disneyland, died in agony shortly afterwards, his face smeared with poison.

The women, who faced death by hanging if convicted of murder, went on trial in October 2017 but the case was slow-moving due to the large number of witnesses and appeals from the defence teams.

The defence stage of the trial had been due to get under way in March before prosecutors suddenly dropped charges against Aisyah, 27, following intense diplomatic pressure from the Indonesian government.

Vietnam then stepped up pressure for Huong's murder charge to be dropped.

Their initial request was refused, but at the start of April prosecutors offered her a reduced charge, paving the way for her release.

The assassination sparked a furious row between North Korea and Malaysia, previously one of nuclear-armed Pyongyang's few allies, and prompted both countries to expel each other's ambassadors.

Ties have improved in recent times however with Malaysia saying it plans to reopen its embassy in Pyongyang, which was closed shortly after the murder. (AFP)