A lawyer who had an affair with a client will have to face a Court of Three Judges for gross misconduct, following a disciplinary probe.

Mr Lee Terk Yang, who is married, admitted to the tryst with the former air stewardess at a hotel over two days in January 2014.

The man she was in a relationship with at the time made the complaint, according to the report of the disciplinary tribunal released yesterday.

The tribunal, appointed by Chief Justice Sundaresh Menon and comprising Senior Counsel Stanley Lai and lawyer Teo Weng Kie, said Mr Lee's conduct tarnished not only his own reputation, but also "potentially impacts upon the reputation of the legal profession as a whole".

It added that he had romanced his client for over two months, while representing her in ancillary matters in divorce proceedings, and took some time to transfer the case to another law firm.

Mr Lee's lawyer Eugene Thuraisingham argued that the client was not a simple-minded woman who was made use of by him, but was well-educated.

He added that Mr Lee was in a genuine relationship with her and was not being dishonest. Mr Lee, a lawyer of 12 years' standing, did active pro bono legal work and served the Law Society, and is extremely remorseful.

Lawyer Ajaib Haridass, in prosecuting for the Law Society, stressed the serious nature of the misconduct of being romantically involved with a client for whom he was conducting divorce proceedings.

Pointing to the unequal balance of power in the lawyer-client relationship, he added that Mr Lee took advantage in inviting the vulnerable woman to the hotel and it was irrelevant whether the relationship was consensual.

The tribunal found this was a case of "sufficient gravity" to be referred to the Court of Three Judges. It is the highest disciplinary body to deal with lawyers, and has powers to suspend or strike errant lawyers off the rolls, among other things.