The lawyer was found to have been "judge shopping" when he sent an email to court staff asking for a matter to be heard when a particular judge wasn't in town.
The lawyer attached a picture of a monkey, which he said was "a light-hearted attempt to bring some levity to their work".
He claimed he had shared jokes over email with the prosecutor's predecessor and had no reason to disrespect the judge.
The lawyers standards committee fined the attorney $2000.
The ministry's legal aid services general manager, Michele McCreadie, said that since improvements to the legal aid system were made early this decade, the number of complaints about legal aid lawyers had declined and the proportion of substantiated complaints had fallen slightly.
"The large majority are not substantiated through an investigation. Sometimes our investigation shows that the complaint about a lawyer was vexatious," Ms McCreadie said.
The Law Society's legal services committee convenor, Liz Bulger, said the number of complaints about legal aid lawyers was decreasing as the number of legal aid grants fell, and because of the quality checks in place.