The woman at the centre of the sex-for-contracts scandal involving former Central Narcorics Bureau chief Ng Boon Gay was at one time worried that he may have got her pregnant.

Ms Cecilia Sue, 36, had said that in one of her statements to the Corrupt Practices Investigation Bureau, when she was interviewed some five months ago.

But in court on Friday, she vehemently denied that the information contained in the statement, which was the 10th she had given to CPIB investigators.

Ms Sue said in her testimony, that she had asked Ng whether he loved her, and mentioned how she had ended their relationship when Ng seemed unconcerned whether he may have fathered the baby she was carrying.

She also added during cross-examination that she had lied because she was "fearful" of Ng and wanted to make things better towards the end of the graft probe, by trying not to implicate him.

"I'm really fearful of the accused (Ng)," said Ms Sue.

"(He was) so well connected (with) high ranking officers, he has been telling me how he does raid and how he scheme his plan and all that.

"At that time I seriously do not know whether he is connected with CPIB as well, so I just need to close it off and close it off in a nice way."

Ng, 46, faces four counts of obtaining oral sex in exchange for showing favours when Ms Sue was a sales manager at Hitachi Data Systems (HDS) and Oracle Corporation Singapore. He can be fined up to $100,000 or jailed for up to five years on each charge.

The defence's case has been that he and Ms Sue were having an affair since 2009, two years before the first of the four alleged occasions he forced her to give him oral sex.

It was earlier revealed by the defence in court on Thursday that Ms Sue had also CPIB investigators in December last year that Ng had sex with her at a Great World City apartment in June 2009.

But the former IT sales manager denied repeatedly that they had consensual sexual intercourse during cross-examination on Thursday.

The trial continues on Friday.