South Australian Police Commissioner Grant Stevens has identified himself as the high-ranking officer under investigation for accidentally firing his gun during a drug raid in 1991, and admitted someone could be trying to undermine him by bringing it to the fore. 

The incident occurred when Stevens was a 28-year-old officer in the Elizabeth Criminal Investigation Branch (CIB) and has prompted a fresh internal review.

The commissioner confirmed the incident followed a media report over the weekend. 

"In the course of trying to force entry... I accidentally discharged my firearm," he said. 

No one was injured and Stevens said the incident was the subject of an internal investigation at the time.

As for why it's surfaced three decades on, Stevens said he isn't sure.

"I can't comment on the motivations for whoever relayed this incident to a journalist, but it is what it is," he said. 

"I don't shy away from it and it certainly doesn't distract me from the job I'm doing today.

"I don't know what the motivation is, I don't know who's disclosed the story – it's not something I've shied away from."

Usually at this point in an investigation, the identity of the officer in question is protected, however Stevens chose to out himself in part to remove suspicion from other senior police.

The South Australian government has expressed its full support for Stevens. 

"We have 100 per cent faith in the police commissioner, we back him 100 per cent," cabinet minister Nick Champion said.

This article was produced with the assistance of 9ExPress.