Huong burst into tears as a prosecutor announced that the attorney-general had rejected a request to free her; and that her trial would be adjourned until April 1.
The Vietnamese woman accused of the murder of Kim Chol or Kim Jong-nam, elder brother of North Korean leader Kim Jong-un, underwent a physical and mental examination today at the Kuala Lumpur Hospital.
Teh told the court the rejection of Vietnam's request was "perverse", and a case of discrimination, as the attorney-general had favoured one party over another, since the court had ordered both to enter their defence.
Huong's lawyer said he would make a second bid to get the charge against her dropped, and criticised the failure to free her following the release of the Indonesian, Siti Aisyah.
Abdul Rashid Ismail, a leading Malaysian criminal lawyer who was not involved in the case, said the decision to prosecute Huong but not Aisyah was "clearly unfair".
Vietnam's government said earlier that Foreign Minister Pham Binh Binh had asked Malaysia to "ensure a fair trial for Huong and set her free".
Teh rejected speculation that Siti Aisyah's release was due to a lack of video evidence against her, saying the court had already established a case against both.
The two women were the only people in custody after four North Korean suspects fled the country the morning of February 13, 2017, when Kim Jong Nam was poisoned with VX nerve agent.
The legal teams of both women have argued that they were pawns in the audacious assassination of Kim Jong-nam, 45, that was orchestrated behind-the-scenes by North Korean agents.
Analysts said Aisyah's release was in part due to politics and the improved relations between Indonesia and Malaysia that have come since Mahathir Mohamad returned to the Malaysian premiership previous year after the stunning election defeat of Najib Razak.
Last August, a High Court judge found there was enough evidence to show that Aisyah, Huong and the four North Koreans had worked together on a plan to kill Kim. Under Malaysian law, intent to kill is critical to a murder charge. "More so in this case because two people were charged, but it was withdrawn against one but not against the other". The defense part of the trial was to have started Monday.
Hương said she was innocent and wished to continue receiving support from relevant agencies. They say the prosecution has failed to show the women had any intention to kill.
Huong cried as she spoke to Vietnamese Embassy officials after Thursday's court hearing ended.
During the prosecution phase of the trial, expert witnesses testified that acute VX poisoning caused Kim's death and the nerve agent was detected on his face, in his eyes and on his clothing.
Huong's father, Doan Van Thanh, said: "We are very shocked, very sad and we don't understand why it turned out this way".
Huong could face a death sentence if she is convicted. The North Korean embassy in Kuala Lumpur was defaced with graffiti just hours before the trial was to resume.
Malaysian officials have never officially accused North Korea and have made it clear they don't want the trial politicized.