The sex-for-grades corruption trial was on Friday, adjourned again because law professor Tey Tsun Hang was unable to see the Institute of Mental Health (IMH) psychiatrist he was referred to on the previous day.

The forensic psychiatrist, Dr Bharat Saluja, was attending to another case in Changi Prison on Thursday, the court heard.

The case has been adjourned to Monday, April 22.

Tey was supposed to undergo a forensic psychiatric evaluation to determine if he is fit to continue to stand trial, after he suffered what seemed like a panic attack in court on Wednesday.

Chief District Judge Tan Siong Thye asked if the Attorney-General Chambers could expedite the situation, to which Deputy Public Prosecutor Andre Jumabhoy said they would "endeavour to" do so.

"I don't want a situation like yesterday... I'm very sure there are other forensic psychiatrists in IMH who can attend to him," said the judge. "Otherwise this trial is left in a suspense."

Tey, who is on trial for six counts of corruptly obtaining gifts and sex from former student Darinne Ko in exchange for better grades, was diagnosed by National University Hospital (NUH) psychiatrists to have suffered an "acute hyperventilation episode" in court on Wednesday and prescribed Xanax to alleviate his anxiety.

The 41-year-old was discharged from NUH on Thursday and referred to IMH for a forensic psychiatric evaluation, which will establish if he can continue to stand trial.