A man jailed for 14.5 years after biting off a district councillor's ear during the 2019 protests has been given permission to challenge his punishment.

Joe Chen was convicted in December 2021 of three counts of wounding with intent and one count of common assault, for biting off Andrew Chiu's left ear and attacking three other people with a knife outside Cityplaza in Taikoo Shing.

Chen's lawyers told the Court of Appeal on Tuesday that the trial judge didn't fully take into account some mitigating factors, including that Chen suffered from depression and alcohol addiction at the time of his attack.

They said the judge adopted a starting point for the sentence that was too high, and that none of the punishments for the different offences should be served consecutively.

In response, a prosecutor pointed out that the four victims in the incident had suffered physical and mental trauma, adding that the sentence meted out was within the scope of what was allowed.

In granting permission for an appeal, judge Derek Pang said that although the case was "very serious" and "unacceptable", it could be argued that Chen's punishment was excessive.