The man had been having a belated 18th birthday celebration with several friends on Sunday night. The incident happened just after midnight.
''During the night, he became agitated and angry and went and got the air gun he'd recently purchased and fired it a number of times, out on the street,'' Sergeant Derek Ealson said.
The man's companions, who had been drinking but ''were not as intoxicated as him'', were forced to take cover behind a fence and wheelie-bin when the man aimed the air rifle in their direction, Sgt Ealson said.
An 18-year-old man was shot and the slug pellet remained lodged in his knee. He received medical treatment, but was not admitted to hospital.
He was taken to Dunedin Hospital yesterday to have the injury assessed and was likely to have surgery today to remove the pellet, Sgt Ealson said.
''It was very lucky in the circumstances that more people did not receive injuries and no greater injury was suffered.''
The incident was an example of the dangers of mixing firearms and alcohol, he said.
Inquiries were continuing and more charges could be laid, Sgt Ealson said.
• An 18-year-old Alexandra man appeared in the Alexandra District Court yesterday on a charge of causing injury by using an airgun carelessly.
He was remanded to August 21. The bail conditions included a ban on him possessing a firearm or applying for a firearms licence.
