A special constable who bashed a self-described "midget" has escaped jail, but will have to undertake anger management treatment.

Fadi Chafei, 41, was found guilty last month of assault occasioning in actual bodily harm against homeless man Heath Kelly, 31, outside a Surry Hills pub in Sydney's inner city in November 2012.

He was also found guilty of intimidating bystander Matthew Harper who stopped Chafei from leaving the scene by making a citizen's arrest.

Chafei's defence claimed he was acting in self defence.

Magistrate Harriet Grahame sentenced Chafei to a two-year good behaviour bond at Downing Centre Local Court on Tuesday.

He has also been fined $1000 and will have to complete 500 hours of community service, including 50 hours of anger management programs.

A special constable is not a sworn police officer but a person involved in law enforcement for agencies such as local councils.

Ms Grahame said she accepted Chafei was generally of good character and had acted on a "spontaneous outburst of rage".

Nevertheless, the sentence needed to send a strong message to the community about the seriousness of one-punch assaults.

"It was my first thought that this was a matter of such seriousness that he should be incarcerated for it," she said.

"The victim was a much weaker, clearly intoxicated person who was rendered unconscious," she said.

The court previously heard that on the night of the incident Chafei told Mr Kelly, who is just over half his height, to "shut your f***ing mouth" before punching him.

Mr Kelly then fell, striking his head on the pavement.

Chafei then said to an unconscious Mr Kelly "you just learnt your lesson" before he turned to Mr Harper and sneered, "do you want to have a go c***".

In Mr Kelly's statement he said that "no one expects a fully grown man to come up to a midget and smash the f*** out of him".

Chafei's defence lawyer Michael Coroneos on Tuesday described the focus on so-called coward punches, which have resulted in multiple deaths recently, as a "media beat-up".

"They are not new, yet we've got this frenzy from the media about these one-punch cases," he said.

Mr Kelly was not in court for the sentencing.

AAP