NSW Premier Gladys Berejiklian has backed her police minister after it emerged he may have broken the law by firing a prohibited submachine gun at a rifle range on Sydney's outskirts.
David Elliott, who was corrections minister at the time, was holding the gun and a pistol in photographs posted to his official Facebook page in 2018.
The photos marked the opening of the rifle range at John Morony Correctional Complex.
Mr Elliott in a statement this week said he'd asked the police commissioner to investigate after being advised Corrective Services NSW potentially breached the Firearms Act "with respect to potentially hundreds of people, including myself, who have used the range".
Ms Berejiklian on Thursday defended the police and emergency services minister, saying it was a serious matter for corrections and the onus was on them to respond to police inquiries.
She noted CSNSW had issued a public apology to Mr Elliott.
"As I understand it, there are potentially a number of people who through no fault of their own and potentially through the fault of a corrections oversight or lack of compliance have found themselves in this situation," the premier told a budget estimates hearing.
Ms Berejiklian said she spoke to Mr Elliott and was "absolutely convinced that what he did was with full belief and knowledge that corrections have complied completely with the requirements".
When asked why she didn't stand the police minister down while the investigation played out, she again referred to the apology by corrections and said Mr Elliott had not been singled out.
NSW opposition leader Jodi McKay later accused the premier of not acting on the issue to protect her own position in cabinet and the party room.
She said police should not have to investigate their own minister.
"Because this man is in a different faction to her, that is what she is doing, she is protecting her own interests here," Ms McKay told reporters in Sydney.
"If she was acting in the interests of the people of NSW and what is allowed under the Firearms Act ... she would stand him aside."
The unauthorised possession or use of pistols or prohibited firearms carries a maximum sentence of 14 years' jail.
Mr Elliott earlier this week told an estimates hearing he acted in good faith.
CSNSW apologised to the minister "for any embarrassment caused by actions at its weapons range ... and any suggestion he has done something wrong".