The state's Law Enforcement Conduct Commission found the inspector guilty of serious misconduct but stopped short of finding other police tried to cover up the May 2023 incident when they did not publicly declare it.
The 46-year-old crashed a work-issued vehicle in a northern Sydney tunnel and left it damaged on a street after a lengthy, late-night drinking session with colleagues in the city.
Criminal investigators found CCTV evidence he'd consumed 23.6 standard drinks over nearly nine hours, way more than the eight mid-strength beers he told his supervisor he had.
However, he was not charged with high-range drink driving until nearly six months later.
A police watchdog has found a senior officer guilty of serious misconduct for leaving a crash scene. (Joel Carrett/AAP PHOTOS)
The commission found the officer, whose identity has been suppressed by a court, guilty of serious misconduct for leaving the scene of the crash to avoid a blood-alcohol reading.
It also declared he had been "deliberately dishonest" in his answers on an insurance claim form for the crashed car.
Remarkably, the police insurance form had no positive requirement for the officer to declare alcohol consumption, instead simply asking if he had been tested for drinking after the crash.
But the commission found he withheld critical information by not making a declaration in a section summarising the accident, where he wrote he had fallen asleep at the wheel.
The officer was also treated more leniently by his commander and in a police review of his driving, which the watchdog said led to other officers losing confidence in the integrity of the force.
The commission recommended NSW Police Commissioner Karen Webb "consider taking action to terminate the officer's employment", noting his "prestigious position" within the force.
Ms Webb admitted it was a "dark day" for the force but denied the officer received special treatment given he had been hit with criminal charges.
She would not comment on the suggestion she sack the officer, given she triggered an internal complaints process after receiving the report.
Ms Webb also referred concerns officers were using encrypted messaging services, to the Public Affairs Branch.
Commission chief Peter Johnson acknowledged the general public had the right to know that police officers were dealt with the same way as other citizens when alleged criminal incidents occur.
"But there is a second important audience ... other NSW police force officers watch to see if senior officers are dealt with in the same way as junior officers," he said.
Police did not issue a public statement about the allegations until media reported them, prompting suggestions its leadership wanted to cover up the events.
But the commission found no evidence the lack of public disclosure involved impropriety, while noting it had hurt the reputation of the force.
Premier Chris Minns says the public should have confidence action will be taken when it is needed. (Bianca De Marchi/AAP PHOTOS)
Greens MP Sue Higginson said the "outright lying and gross misconduct" was emblematic of a "culture of impunity and cover-up" within the force.
"We simply don't have an effective police integrity and accountability system ... the LECC does excellent work but it is reactive, has limited resources and powers and is routinely obstructed by police in the courts," she said.
Premier Chris Minns disagreed, suggesting LECC investigations had resulted in charges against officers numerous times.
"I'm not suggesting when you've got an organisation as big as NSW Police there won't be issues from time to time but the public should have confidence there are independent oversight agencies that will take action when it's needed," he said.
The officer is due back in court on September 27.
