Lawyer Lee Suet Fern has been found guilty by a disciplinary tribunal of grossly improper professional conduct in her handling of the last will of Mr Lee Kuan Yew, Singapore's first prime minister and her father-in-law.

Her case will be referred to the Court of Three Judges, the highest disciplinary body to deal with lawyers' misconduct, and she could face a fine, suspension or be disbarred as a lawyer.

In its report released last week, the two-man tribunal appointed by Chief Justice Sundaresh Menon described Mrs Lee as a "deceitful witness, who tailored her evidence to portray herself as an innocent victim who had been maligned".

It also found the conduct of Mrs Lee's husband, Mr Lee Hsien Yang, "equally deceitful", saying he lied to the public and the tribunal and tried to hide how he and his wife had misled Mr Lee Kuan Yew.

The couple also sought to suppress relevant evidence, it said.

The Attorney-General's Chambers had referred Mrs Lee's case to the Law Society, which filed the charges against her, last year. It said her actions were a breach of rules on conduct as her husband was a beneficiary in the will.