The Independent Police Conduct Authority has found no evidence that Commissioner Howard Broad "pulled rank" and refused a breath test in the early 1990s.
Journalist Ian Wishart alleged in his book, Absolute Power: The Helen Clark Years, that a drunk then Detective Inspector Broad told a police officer "Don't you know who I am", or words to that effect, when stopped in Christchurch in 1992.
Authority investigators have interviewed 16 police and traffic officers working in Christchurch in 1992.
None of those officers claimed any direct knowledge of Mr Broad being stopped at a checkpoint, it said in a report released today.
"Our investigation was independent and thorough, and found no evidence of misconduct," authority chairwoman Justice Lowell Goddard said.
"Not a single person we spoke to claims to have been present or to have any first hand knowledge of any occasion when Mr Broad was stopped at a checkpoint and refused a breath test.
"Such claims are based on hearsay."
The authority confirmed Mr Broad - then a detective inspector - was stopped by a traffic officer in May or June 1992 after a meal at a restaurant with other officers.
Mr Broad had consumed alcohol and admitted having done so.
Those present confirmed Mr Broad co-operated with the traffic officer. He was given a breath screening test which indicated alcohol on his breath.
The traffic officer did not believe any further breath testing was necessary.
He told Mr Broad to leave his car and walk, which was common traffic enforcement practice at the time.
The following morning, Mr Broad told his supervisor about the incident.
Justice Goddard was satisfied that the traffic incident was dealt with appropriately at the time, according to the laws and policies of the day.
She was also satisfied that the traffic stop was the incident referred to in Mr Wishart's complaint, and that there was no evidence of any other similar incident involving Mr Broad.
An earlier investigation by State Services Commissioner Mark Prebble also found the allegations to be false.