Pressure has been building from senior members of the legal profession on a Supreme Court judge to resign.

Justice Bill Wilson has been accused of a "serious breach of judicial ethics" by one of the country's most distinguished former judges.

Sir Edmund (Ted) Thomas, formerly of the Court of Appeal, wrote an 18-page complaint to the Judicial Conduct Commissioner, raising concerns that Justice Wilson had failed to fully disclose a debt he owed a senior lawyer at a time the lawyer argued a case before him.

If a judge acted in a way as to mislead a court, Sir Edmund wrote, the court and not just the judge would be tarnished.

"There is a real risk that the court will be seen as dysfunctional. The court, and not just the individual judge, is brought into disrepute."

Sir Edmund's complaint sets out respects in which he asserts Justice Wilson failed to meet required ethical standards of judicial conduct.

He added: "Based on my 43 years' or so experience at the bar and on the bench, I believe that any other judge I have known would have stood down or made a complete disclosure."

According to a copy of his complaint obtained by the Weekend Herald, he considers the matter is too serious for the conduct commissioner to refer it to Chief Justice Sian Elias.

He wrote that this course of action should be ruled out because of the horse-racing interests Dame Sian, her husband, Hugh Fletcher, and Justice Wilson shared until recently.

His complaint also says that three of the country's top QCs had agreed to approach the judge and persuade him to resign.

The controversy arises from Justice Wilson's failure to disclose that he owed nearly a quarter of a million dollars to Queen's Counsel Alan Galbraith and to withdraw from a Court of Appeal case (Saxmere Company v Wool Board Disestablishment Company) in which Mr Galbraith appeared for the Wool Board company.

Sir Edmund's complaint also notes that Justice Wilson sat on four other cases in which Mr Galbraith appeared at a time when the judge was "substantially" in debt to the QC.

He said this raised the possibility of a right to retrial.

Checks by the Weekend Herald indicate two of the court's decisions went in favour of Mr Galbraith's clients, one against and a third case is ongoing.

In a fifth case known to the Weekend Herald, the decision also went against Mr Galbraith.

Solicitor-General David Collins, QC, was one of the lawyers opposing Mr Galbraith in one of those cases.

Sir Edmund said in his complaint that he did not know if Justice Wilson made disclosures in those cases.

The complaint also says Mr Galbraith had pressed Justice Wilson for payment of his debt from 2007, and that the QC had also signed a bank guarantee for the judge which was not disclosed to the court.

Sir Edmund's complaint implies that some judges and lawyers have lost confidence in Justice Wilson.

It focuses on Justice Wilson's conduct regarding the Saxmere case, and whether that amounts to a serious breach of judicial ethics.

Sir Edmund raised four concerns:

* The Chief Justice had told him that Justice Wilson had given her a "categorical assurance" that he was not "beholden" to Mr Galbraith "when he knew he was substantially indebted" to the Queen's Counsel.

* Justice Wilson's failure to disclose his substantial indebtedness to Mr Galbraith.

* Justice Wilson's failure to take action to correct the court's Pressure on judge to resign over 'breach of ethics' misapprehension - set out in its judgment of July 3 - that there was no such indebtedness.

* Justice Wilson's failure to make appropriate disclosure, knowing it was relevant to Saxmere's right to apply to have the order against it recalled and obtain a retrial.

Saxmere is a producer of superfine wool. Its $8 million lawsuit relates to levies it claims it is owed by the old Wool Board.

It won its case in the High Court, but then lost in the Court of Appeal, where Justice Wilson was on the three-judge panel.

Saxmere appealed, saying the judge should have withdrawn because of his links to Mr Galbraith.

Last July, the Supreme Court found that "a fair-minded observer would not have had a reasonable apprehension of bias" arising from the personal and business (land and racehorse interests) relationship Justice Wilson had with Mr Galbraith.

It was only after Saxmere came back to the Supreme Court that - under direct questioning by his fellow Supreme Court judges - Justice Wilson revealed that at the relevant time he owed Mr Galbraith $242,804.

This declaration came after a series of partial disclosures over two years by Justice Wilson.

As a result, the court recalled its judgment and sent the case back for re-hearing in the Court of Appeal.

Judicial Conduct Commissioner Sir David Gascoigne - assisted by former Australia Chief Justice Murray Gleeson - is also considering an earlier complaint by Saxmere regarding Justice Wilson's failure to withdraw from the case "despite the nature and extent of his financial relationship with counsel in the case".

The commissioner can dismiss the complaint, refer it to the Chief Justice or recommend to the Attorney-General that he appoint a Judicial Conduct Panel for an inquiry.

* Sir Edmund is a retired judge of the Court of Appeal who was also called upon to sit on the Supreme Court. He is a former president of the Law Practitioners Disciplinary Tribunal and a non-executive director of the Reserve Bank.

* He has been involved in several landmark cases. As a Queen's Counsel, he successfully argued that the proposed 1985 All Black tour to South Africa should be stopped. He also succeeded in the "ticks and crosses case" which changed electoral law so that votes had to be counted in all instances where the voter's intention was clear.

* He was a member of the Court of Appeal panel whose decision in 1998 contradicted Sir Ronald Davison's Winebox Inquiry finding that there was no fraud.