Carl Murphy, 38, was slapped with a 12 month good behaviour bond for committing an act of indecency without consent and must attend rehab and accept supervision from ACT Corrective Services.

He was also sentenced for unrelated matters, including possessing two large knives in Civic and consuming liquor in an unauthorised place.

The knife charge attracted a four month prison sentence, but considering Murphy had already spent more than five months in jail he was released having served his time.

The act of indecency occurred on a busy Friday night just before 6pm at the skate park on Cooyong Street. A woman, cycling home from work, called the police saying she had witnessed a man and woman having sex but held fears the woman was unconscious.

The officers reported when they arrived at the skate park they located Mr Murphy and the woman having sex. The woman was conscious and the intercourse was consensual.

Prosecutor Sofia Janackovic described the incident as brazen sexual activity and said Murphy had been reckless.

However, Murphy's defence lawyer Tom Taylor said Murphy, due to intoxication, had no idea there were people around and had not intended to cause anyone offence by his actions.

He said his client's actions should not be compared to other instances where this charge is applied, for example, an individual masturbating in public.

Magistrate Bernadette Boss agreed and described the public intercourse as an unpleasantness rather than mainstream sexual offending.

Mr Taylor said his client was devastated by what he had done, was taking steps to curtail his alcohol addiction and had Murphy not been homeless at the time this offence may never have come to pass.

Dr Boss said while his actions were not malicious, people living in a civilised society did not behave in the way Murphy had. She said a child could have witnessed the intercourse and people had a right not to witness such things publicly.

She was also blunt in telling Murphy he needed to get in control of his alcohol addiction and he should start by looking in the mirror.

"You're growing old before your time because of your addiction," Dr Boss said.

"You're probably going to die in jail if you don't get in control of your addiction."

Mr Taylor said it had been a difficult time for his client but he respected the court's decision.

"Mr Murphy’s case highlights some of the issues with homelessness that might otherwise be overlooked," Mr Taylor said.

"We may think that homelessness is as simple as a lack of housing, food and clothing but it is really much more than that."