Thomas Edward Churchill, 77, was sentenced in the Dunedin District Court last week after earlier pleading guilty to doing an indecent act.
The court heard that between 1981 and 1982 Churchill requested the girl perform a lewd act while he was in a barn.
On another occasion, the defendant approached the girl and asked her to touch his penis, which she declined to do.
But Churchill persisted and asked multiple times before she ran away.
When the girl’s mother found out, she confronted the defendant and he admitted exposing himself to the victim, but denied asking her to inappropriately touch him.
Churchill is a retired firefighter and had been the treasurer for the Dunedin Fire Brigade Restoration Society, attending children’s events and rallies as part of the group.
The society committee said it was "completely unaware" of Churchill’s offending.
"Mr Churchill resigned from the Dunedin Fire Brigade Restoration Society in September 2017, and has not been affiliated with the society in any capacity since that date."
In a statement to the court, the victim — now aged in her 50s — said she was concerned Churchill was involved with children in his role, and wished she reported him sooner.
"I wish I spoke up. I wish I protected others. I wish I stopped his behaviour way back then.
"I want the world to be protected from him."
She did not believe Churchill was sorry for the harm he had caused.
"Over the last 40 years of my life, I have lived in a prison of confusion," the victim said.
"I honestly believe that it would’ve been easier if he just murdered me as opposed to [abusing] me."
She said the offending continued to affect her life, but she hoped she could start anew after the sentencing.
"I know that I do not forgive him. I will never forgive him"
Counsel Alexandra Bligh said her client was "incredibly ashamed and embarrassed" to be before the court.
"It hasn’t been a secret; it has been acknowledged by my client [throughout] his entire life."
The victim requested emotional harm reparation, but Ms Bligh said that was unrealistic as Churchill was "in dire financial straits".
Judge Dominic Flatley said the offending seemed to be a one-off and Churchill had positively contributed to the community since.
"This offending appears to have been isolated and occurred at a very different time in your life," Judge Flatley said.
"You are remorseful, you have apologised many times."
He sentenced Churchill to four months’ community detention and did not order Churchill to pay emotional harm reparation.