Instead of star witness Darinne Ko returning to the witness stand to give evidence, the first hours of the sex-for-grades trial on Friday were spent dealing with an application by law professor Tey Tsun Hang.

Tey, who is facing six charges of corruptly obtaining gifts and sex from Ms Ko in exchange for better grades, had asked the court for access to documents he had previously sought for last year.

These include documents containing the academic grades of former National University of Singapore (NUS) students, including that of Ms Ko and statements by NUS staff who are involved in the ongoing trial.

Tey, 41, had made a request for information from the university in court last August, but was told by the judge then that it was a premature application.

Friday's hearing was adjourned in the morning for a short recess, for the matter to be resolved in chambers, but it not successful.

Chief District Judge Tan Siong Thye, the trial judge, then decided to hear the application, which contained more than 44 paragraphs, line-by-line in open court.

All this, while star witness Ms Ko waited for her turn to return to the stand in the witness room.

Tey, however, was admonished by Justice Tan for "having wasted considerable time" in the morning, when the proceedings resumed after lunch.

This after the prosecution informed the court that Tey, had in possession nine of the items that were being deliberated in the morning.

When pressed by the court when he had received the affidavit filed, Tey said " last year" and admitted that it "should still be in (his) office".