Julian Real (41), who served in Dunedin during his almost 10-year police career, claimed to have missed out on thousands of dollars in competency payments during that time.
Nor, he claimed, was he alone.
Mr Real alleged those who graduated from the Royal New Zealand Police College wings 200-205 - an estimated 350 officers - had been underpaid compared with those graduating before and after them.
Officers of those wings confirmed to the Otago Daily Times they had received compensation in the form of $3000 "goodwill payments".
However, some affected officers could have been underpaid about $10,000 in competency payments, which reward those who pass competencies such as fitness tests.
The underpayments throughout the force could amount to an estimated $2.8 million, but former officers such as Mr Real received no compensation or notification.
"I can understand the police might not be able to afford to pay $2 million or whatever it was, but why should I, and my colleagues in those wings be disadvantaged for a mistake not of our doing," Mr Real asked.
He had made inquiries to police and the New Zealand Police Association, but had not received a satisfactory response.
"I want an apology. I want them to be open and I want other people in my situation to be aware of this mistake."
The ODT contacted Police Minister Anne Tolley's office, but inquiries were referred to Police National Headquarters.
In an emailed response, a police spokeswoman said: "There was no universal mistake made in the pay for the staff of those wings, nor was there any pay they were meant to receive but did not.
"The staff from those wings were on remuneration bands precisely in accordance with the terms of the collective employment agreement."
It is understood police have no obligation to pay the underpayments, as the payment loophole was ratified by its union.
The newspaper is seeking a release of documents via the Official Information Act.
Police Association president Greg O'Connor did not return calls.
