Malaysian Prime Minister Najib Razak and his former chief aide Musa Safri may be called to give evidence in a civil suit filed by the father of a murdered Mongolian interpreter.

Lawyer Ramkarpal Singh, who is representing Altantuya Shaariibuu's father Setev, said the stalled lawsuit could now proceed after the Federal Court on Tuesday upheld the death penalty of two police commandos - Chief Inspector Azilah Hadri and Corporal Sirul Azhar Umar, Malaysian Insider reported.

The two men had been convicted of the 2006 killing of the 28-year-old model and interpreter, but were acquitted later.

"Najib and Musa will be subpoenaed to testify in the case. But I do not know if they will attempt to make applications to exempt them from coming to court," the lawyer told the Malaysian Insider.

The woman's father filed the RM100 million (S$37 million) civil suit in June 2007 but it was stalled due to the criminal trial, according to the report.

"The suit was in the backburner because the high court wanted the criminal trial to be concluded first," Ramkarpal said.

He was quoted as saying he would be writing to the Shah Alam High Court to fix a date for case management so that the trial could be held as soon as possible.

Setev filed the suit on behalf of his wife and their two grandsons who were minors. The couple are guardians of the children, the younger of whom suffers from a medical disorder which requires expensive treatment, said the report.

The family is seeking damages for "suffering, sorrow, as well as physical and mental anguish".

Government critics have long alleged that Azilah Hadri and Sirul Azhar Umar, from an elite unit that guards top ministers, were scapegoats in the killing of Altantuya, who was at the centre of allegations of kickbacks in a €1.1 billion (S$1.72 billion) purchase of French Scorpene submarines in 2002.

The remains of Altantuya, who was involved in negotiations for the submarines, were found in a jungle clearing near Kuala Lumpur after she was apparently shot and her body blown up with explosives.

Adding to the intrigue, she was a lover of Abdul Razak Baginda - the man in charge of purchasing the submarines and a close associate of Prime Minister Najib, who was defence minister at the time.

Allegations have simmered for years that she was murdered to keep her quiet about kickbacks to high-level Malaysian officials.