An updated guide on judges' conduct published by the judiciary on Monday says judges should avoid expressing views to the media, even anonymously, and be wary of liking or following any person or group on social media if doing so could undermine people’s perception of their impartiality.

In a statement, the judiciary said now is an appropriate time to update the Guide to Judicial Conduct, published in 2004, given what it called "the increasing complex conditions where judging takes place" and higher public interest in judges' work.

Five judges were part of a working party tasked to update the guide. They are chief judge of the High Court Jeremy Poon, Court of Appeal judges Thomas Au and Godfrey Lam, chief district judge Justin Ko and chief magistrate Victor So.

Most of the original guidelines were retained in the updated version, but there are a number of new additions. Some concern the judicial duties of judges, others their private activities.

For example, judges are reminded that any criticism they make in court against a person should be relevant, necessary, justified and “tempered with caution and restraint”.

A new section on the use of social media says judges can choose whether to use social media in their private activities, but they should be aware of the risks. “In general, a judge should not use social media in any way that would pose risks to the judge or compromise his or her standing and integrity or the dignity of the office or public confidence in the judiciary generally if the relevant information became public,” it says.

For example, judges should be wary of "friending", "liking" or "following" any person or group if such association may “undermine the perception of their impartiality in a particular case” or could damage public confidence in the judiciary.

On the professional activities of judges outside court, the guide says there is no objection to judges contributing to legal and professional education by delivering lectures, teaching, taking part in conferences, or writing legal texts as authors or editors.

But it says judges should avoid expressing views to the media, even on an anonymous basis. The guide adds that media enquiries should be directed to the court leader, who will generally refer them to the judiciary's press office.

Judges should also be wary of appearing to be associated with others, such as organisers of conferences or book authors, if such association is “likely to be controversial”, adding that they should avoid expressing views “extra-judicially on controversial issues”.

The new guide also says judges should not join or make contributions to political organisations and activities. “Judges should also refrain from making public statements or petitions, whether or not jointly with others, on matters of a political or controversial nature,” it adds.

The guide noted that there had been cases where judges were subject to online abuse or doxxing, but judges should refrain from responding directly to such attacks.

"I am confident that this new edition of the guide will continue to provide useful guidance to judges and judicial officers in maintaining the highest standards of judicial conduct, and enable the public to better understand our judicial work and the uncompromised standards we set for ourselves," chief justice Andrew Cheung said.