Thomson scaled the wire gates, walked to a large crane and climbed up on its boom until he was about 20m from the ground.
Police were alerted by a member of the public via phone.
Emergency services and the construction site managers attended the incident, retrieving Thomson from the crane using a nearby cherry picker.
When questioned by the police, Thomson said he was, ''extremely intoxicated and simply wanted a better view of Invercargill''.
After he sobered up, he said he could not recall entering the yard or climbing a crane.
Thomson also faced charges of disorderly behaviour and wilful trespass in relation to a private party two days after the incident.
On March 6, several 16-year-olds were setting up a birthday party at the Blues Rugby Club rooms in Conon St, Invercargill.
The summary of facts stated Thomson arrived at the address in an intoxicated state, entered the building uninvited and while there, made derogatory and sexual remarks about the 16-year-old females' appearance.
The adults present asked the defendant to leave immediately.
He refused to do so, saying he was staying for the party.
Thomson continued to make lewd comments until he left the building.
Police located him outside and arrested him.
He declined to provide an explanation.
Thomson was sentenced to 60 hours' community service and six months' supervision.
