Vietnam is calling on Malaysia to free Vietnamese Doan Thi Huong accused in the 2017 murder of the North Korean leader's half brother, Kim Jong Nam.

Vietnam's Foreign Minister Pham Binh Binh, in a telephone call to his Malaysian counterpart Datuk Saifuddin Abdullah, asked Malaysia to "ensure a fair trial and free Huong.

Huong's co-defendant, Indonesian Siti Aisyah, was freed on Monday after the Shah Alam High court dropped the charge against her.

Huong is set to appear in court on Thursday after her lawyers asked the Attorney-General to withdraw her murder charge.