A former senior staffer to Malcolm Turnbull has pleaded guilty to charges of offensive behaviour and drug possession.

Magistrate Maria Doogan said in her sentencing there had been a "significant" impact on Ellis's life already.

"What happened on this particular day has ultimately become a tragedy for you," Ms Doogan said.

She also went on to describe the incident as "bizarre", saying Ellis's culpability was affected by his intoxication.

"Nobody could make this up," Ms Doogan said.

"Nobody who wasn't under the influence... would behave in such a way in a public place, especially an airport."

Ms Doogan found the two offences had been proved but she handed down a non-conviction order for both.

Ellis originally additional charges, but they were dropped by the prosecution or dismissed.

Ellis's lawyers had argued that given the media attention surrounding the criminal matters last year, he had already been punished enough.

They said Ellis had lost professional standing and damaged his reputation to the point where he was unable to secure anything more than contract work.

As well as the damage to his career, Ellis's lawyers argued the charges had made it more difficult for him to visit the United States, where his partner is from and frequently travels to for work.

Ellis resigned from his government position last year after being charged with the offences, including public indecency and carrying prohibited items through airport security.

The charges related to an incident at Canberra Airport last year when Ellis was working for Mr Turnbull, who was then communications minister.

Ms Doogan said given his lack of criminal history there would be no good behaviour order but she did order him to pay court costs of $73.