A Perth magistrate has described a 21-year-old man who attacked an off-duty cop on his way to work as a bully who roamed Northbridge.

Sonie was described as a 'bully' by the magistrate. Credit:Facebook

Magistrate Richard Huston said Clyde Antonio Sonie's offending behaviour towards police and public officers was "disgusting."

The magistrate made the remarks as he sentenced Sonie over a string of charges in the Perth Magistrates Court on Wednesday.

Sonie was due to stand trial this week on five charges, including three counts of assaulting a public officer, but he ended up pleading guilty to all charges.