Police are investigating one of their own after he allegedly gave false information on police letterhead to have a parking ticket waived.

National manager of youth services Superintendent Bill Harrison wrote to the Wellington City Council after the $200 ticket was issued in September 2008 for a police car not showing a current registration, The Dominion Post reported.

"I attach a copy of the current label that, through an oversight, was incorrectly displayed (behind the old label)," he wrote.

But the newspaper obtained documents showing the registration Mr Harrison attached to his letter was issued an hour after the ticket.

A council spokesman told the newspaper the discrepancy was because the registration Mr Harrison sent to them was a replacement.

Assistant Commissioner Grant Nicholls said police became aware of the incident only last month and started an investigation.

"We are affording the superintendent all the rights of the employment process given to anyone alleged to have failed to meet the standards of behaviours expected in their employment," Mr Nicholls said.