The Future Forward Party (FFP) will ask the government to clarify the mystery surrounding the death of insurgent suspect Abdulloh Esormusor when the House meets on Wednesday.
FFP list-MP and spokeswoman Pannika Wanich said the Defence Ministry owes the public an explanation and the party will press ahead with a planned motion to determine the truth behind Abdulloh's death.
She said the party also plans to call for a review of special security laws in the deep South that are deemed to give overwhelming power to the government and security officers.
According to the FFP MP, Abdulloh was detained for questioning without hard evidence.
Ms Pannika said that she had paid a visit to Abdulloh's family in Pattani's Sai Buri district on Friday and stood behind them in their determination to seek the truth behind his death.
"We'll stand with Abdulloh's family as they fight injustice. We'll seek to abolish the special laws that give the state too much power," she said.
Abdulloh died on Aug 25 of acute pneumonia and septic shock at Songklanagarind Hospital in Songkhla's Hat Yai district, more than a month after he was found unconscious while in custody at the Ingkayutthaboriharn military camp in Pattani province.
He had earlier been arrested at his home after being implicated in insurgent activities in Sai Buri district of Pattani by a leading insurgent named Ibroheng Maseng.
Abdulloh was then taken to the Ingkayutthaboriharn camp for questioning.
He was rushed to the camp hospital, which provided first aid before he was sent to Pattani General Hospital and then to Songklanagarind Hospital.
Doctors said he was suffering from a cerebral oedema, which could have been caused by a lack of oxygen.
Abdulloh's death has renewed concerns about handling and treatment of suspects in the restive southernmost region and it is unclear what caused him to be deprived of oxygen.