The woman at the centre of the corruption charges against former civil defence chief Peter Lim Sin Pang said she had performed a sex act on Lim because she "liked him a lot".

Giving her testimony on her first day on the stand on Monday, Ms Pang Chor Mui, 49, said that she was giving Lim a ride home on May 2, 2010, when the two decided to stop for a chat. One thing led to another, and they ended up kissing and hugging. Soon, she was performing oral sex on Lim.

Lim is charged with corruption for obtaining sexual favours from Ms Pang on that night, in exchange for furthering the business interests of her then-employer Nimrod Engineering. She was a general manager there.

But their tryst was cut short, said Ms Pang, because it had dawned on her that they were in a very public place. While on the stand on Monday, Ms Pang revealed that at the time she had the encounter with Lim, she was in an "intimate relationship" with her boss, managing director of Nimrod Engineering. She said that the relationship was non-sexual, and both parties "cared for each other and supported each other'.