An Auckland lawyer has been censured and fined after his firm prepared an affidavit for a man who was about to retract evidence against one of his clients.

A lawyers standards committee fined former police officer Michael Meyrick $5000 after it found he had failed to take reasonable care in one of his clients' appeals against sentence.

The committee found that Mr Meyrick's firm's oversight of the affidavit was "at the high end of unsatisfactory conduct" after it filed an affidavit described as too general.

It also found that he did not provide competent and independent legal advice.

Mr Meyrick represented client "A" who had been found guilty of multiple violence offences against his son "B" - who was the principal witness at his trial.

The appeal was made after "B" sought to retract his evidence against his father.

"B" filed an affidavit - drafted by Mr Meyrick's firm - saying that he had given untruthful evidence at the trial.

But the Court of Appeal questioned "B" before he gave evidence and raised concerns that he had not received competent and independent legal advice before swearing the affidavit.

It later emerged that the man had spoken with a lawyer on the phone but did not show the lawyer the affidavit, nor did he receive formal written advice.

The court adjourned the hearing and Mr Meyrick withdrew as counsel as a result.

The Ministry of Justice investigated Mr Meyrick's conduct during the appeal and lodged a complaint with the Law Society.

The standards committee said the Court of Appeal had "a number of criticisms regarding the affidavit sworn by B".

"In particular, the court believed that the affidavit was too general and was not happy about the legal advice B had received.

"The court further stated that the firm should not have prepared the affidavit."

The standards committee said that while the conduct was serious and it considered sending the matter to the Lawyers and Conveyancers Disciplinary Tribunal, it found it was not wilful or deliberate.

The committee also ordered publication of Mr Meyrick's name and the determination in the public interest.

It also ordered Mr Meyrick to pay the Law Society $1200 costs.

In 2005, Mr Meyrick was found guilty on four charges of possessing an objectionable publication - images on a computer and disks - and fined $3000.