At the same time, the judiciary has said that a lawyer being under the influence of alcohol might, in some circumstances, constitute grounds for an appeal.

Mr Chan on Thursday said the association would not ask barristers to refrain from drinking before appearances, only that they make sure their drinking did not affect their performance.

He was commenting after the launch of investigations into the antics of prosecutor Roderick Murray in a District Court sentencing on Monday.

Mr Chan reiterated that position yesterday, but said if the practice was causing widespread problems, the association might revisit the issue.

'It's never been a problem before,' Mr Chan said, adding that if a barrister was affected by alcohol, it was likely their assisting solicitors would do something about it, and the barrister's business would no doubt suffer as a result.

'It is not a situation whereby if one's performance is affected by alcohol it will go unnoticed. The reason we do not have hard and fast rules on drinking is because of this practical situation.'

But Prisoners' Friends Association executive council member Alan Crawley said that approach was not good enough.

'It's totally unacceptable that barristers be allowed to go to court in anything less than full control of their faculties,' Mr Crawley said. 'It is indefensible.

'It beggars belief that anyone should seek to defend a lawyer who goes to court to defend a client after he's had a few drinks.'

He said if two glasses of alcohol could affect a person's driving without their noticing, so too could it affect barristers' performance.

'You're not allowed to drive a car if you've had even a tiny amount of alcohol these days and you should not be allowed to drive the carriage of justice forward either,' Mr Crawley said.

A judiciary spokeswoman said lawyers were expected to adhere to strict codes of conduct. 'They should conduct their cases and behave in court according to these principles,' she said.

'The incompetence ... and dereliction of duty of lawyers in the conduct of proceedings on behalf of their clients may ... be relied on as a ground of appeal.'

Solicitor Phyllis Kwong Ka-yin, a candidate for the legal sector, called on the Bar Council to review the regulation. She said that if there was a likelihood drinking would affect their performance, they should refrain in the 'best interests of clients'.

Rival candidate Judy Tong Kei-yuk, said she needed to study the issue, as did legal sector representative Margaret Ng Ngoi-yee.