South Australia’s highest ranking police officer has admitted his conduct was investigated three decades ago after his gun was accidentally fired during a police raid.

SA Police commissioner Grant Stevens said he never “shied” from the investigation into an incident where his gun was accidentally fired during a police raid of a suspected heroin den in the 1990s.

At the time, Stevens was a senior constable with the Elizabeth CIB.

Know the news with the 7NEWS app: Download today

On Wednesday, he admitted to his conduct being investigated over the raid when his gun accidentally discharged 34 years ago.

Grant Stevens was a senior constable with the Elizabeth CIB when he was investigated over an accidental gun discharge. Credit: 7NEWS

“I can confirm there has only ever been one occasion that I have accidentally discharged a firearm in the course of my duty,” he said.

“During the course of trying to gain entry to the house, it became apparent he was trying to dispose of the drugs.

“In the course of forcing entry, I discharged my firearm.

“My supervisor was present at the time, he obviously was aware of the incident, it’s a bit hard to not disclose that.”

Steven said that proper police procedure was followed, including an internal investigation.

“I had to spend a fair bit of time on an old typewriter typing out a police report,” he said.

“Internal investigation branch were notified, and I received managerial guidance which is exactly what would happen to a police officer today.”

Stevens said he is unsure why someone is digging up a documented police incident, that was never kept a secret.

“I can’t comment on the motivations for whoever relayed this incident to a journalist, but it is what it is.

“I don’t shy away from it, and it certainly doesn’t distract me from the job I’m doing today.

“I’ve recounted the story regarding the incident several times over the last 34 years, I’ve never hidden from it or shied away from it.

“As far as I’m concerned, it was handled in accordance with the procedures of the day.”