The sex-for-contracts corruption trial of former Singapore Civil Defence Force (SCDF) chief Peter Lim Sin Pang resumes on Friday.

More SCDF officers are expected on the stand, including Lieutenant-Colonel Wong Kok Buk, who will return to be cross-examined by defence lawyers Hamidul Haq and Bala Chandran.

The assistant director of the SCDF purchasing branch had told the court in February that Lim was remiss when he did not declare his initimate relationship with Ms Pang Chor Mui, a one-time general manager of Nimrod Engineering.

The technology firm had bid for a tender to provide radiation detectors to the SCDF in 2011, before the tender was put up on the Government procurement website GeBiz.

Lim, 52, is accused of having an illicit tryst with her in May 2010, before tipping her off a year later about the contract.

His lawyers have maintained that the pair were merely close friends whose flirting escalated into a one-off sexual encounter.

During the first four days of the trial in Febriary, the prosecution sought to show that Lim was "beholden" to Ms Pang, after their sexual encounter in 2010.

Deputy Public Prosecutor Tan Kiat Pheng said when the first part of the trial ended that the prosecution will be concentrating on Ms Pang's evidence in the second part of the trial, but did not reveal when exactly she would be called to the stand.