SINGAPORE - A controversial lawyer who went on a "demeaning" line of questioning of a molestation victim, including staring at her breasts, was suspended for the maximum of five years on Wednesday (May 2) for professional misconduct.

The Court of Three Judges, the highest disciplinary body for the legal profession, had harsh words for Mr Edmund Wong Sin Yee's "disgraceful" conduct and his "irrelevant and wholly impermissible" line of questioning, which Chief Justice Sundaresh Menon noted had the purpose of humiliating the victim.

To this day, Mr Wong, who was not present in court, maintains he had not done anything wrong, which the court said weighed against him.

"It is extremely difficult to reform one who does not appreciate the error of his ways," said the Chief Justice.

Mr Wong, who runs his own firm S Y Wong Law Chambers, had defended a 24-year-old student from China who was accused of brushing his forearm against the breast of a 22-year-old woman on board an MRT train in July 2014.

While he was cross-examining the victim during the trial in 2015, Mr Wong repeatedly asked the woman if she thought she was attractive and told her that he thought she was pretty.

He then commanded her to stand up and scrutinised her chest.

The victim, feeling offended, asked if this was necessary. Mr Wong retorted that he would be asking even more insulting questions.

When the district judge intervened, Mr Wong sought to justify his line of questioning.

"So I'm trying to put my case that, you know, looking at the day (how) she was dressed and... her breast size and all these things... whether there is temptation for anybody or the accused to do such a thing," he said.

Xu Jiadong was found guilty and jailed for five months by the district judge, who dedicated six pages of his grounds of decision to Mr Wong's "unacceptable" cross-examination.

The Attorney-General's Chambers lodged a complaint with the Law Society.

A disciplinary tribunal found Mr Wong's offensive line of questioning had breached professional conduct rules. The case was referred to the court, which has the power to suspend or disbar lawyers.

On Wednesday, his lawyer, Mr Eugene Thuraisingam, said Mr Wong's focus on attractiveness was aimed at advancing the case that the woman was such a "plain Jane" that the accused had not even noticed her.

The argument did not go down well with the court.

"Are we in the business of beauty contests?" asked Chief Justice Menon.

Judge of Appeal Judith Prakash asked where he had got the idea that only attractive women were molested. She added it was not for Mr Wong to assess the victim's attractiveness but for his client to say so in his testimony.

Judge of Appeal Steven Chong questioned if anyone accused of molestation had ever successfully defended themselves by proving that the victim was "not sufficiently attractive" to be molested.

Mr Wong, who was called to the Bar in 1998, has a long list of past convictions going back more than 20 years. This includes incidents of violence, drug consumption, and abuse of public servants. He was also detained under the Criminal Law (Temporary Provisions) between 2005 and 2012. He resumed practising law three years after his release.

The court said the totality of his conduct showed he had "no meaningful appreciation" of how a lawyer should conduct himself.

Although the question was raised as to whether he was fit to practise law, the judges said they had not struck him off the rolls as many of his violent antecedents were "somewhat dated".

The suspension takes effect in two weeks.

The court will issue detailed written grounds for its decision at a later date.