He also received a discharge without conviction for possession of police pepper spray.
"This is a very tragic way to end a significant career in the police. It is not just a job and when you fall foul of the law yourself that value disintegrates and the network he has formed over 25 years is no longer there," the Timaru Herald reported defence counsel Jonathan Eaton QC as saying.
Clark worked for many years as a sergeant and senior sergeant at Temuka police station.
He has also been a popular community figure, volunteering as a local rugby coach and sitting on a school board.
Sharp retired from the police late last year, police confirmed today.
A police spokeswoman said the case highlights how they hold their own staff to account when they fall foul of the law.
"The public rightly expect the highest standards from police, which is why integrity is one of our core values," the Timaru Herald reported her as saying.
"The overwhelming majority of police staff live these values every day, and it is always disappointing when individuals fall short in this regard."