The police watchdog says two officers took inaccurate notes while interviewing a piano instructor about alleged inappropriate behaviour.
Police received a complaint from a previous student who said the instructor had been inappropriate with her when she was 14.
A spokesperson for the police said the woman did not want to press charges, but supported the officers' decision to carry out a "prevention visit" with the man.
The Independent Police Conduct Authority said the two officers met with the piano instructor at his home on two separate occasions, but did not take notes during the meeting.
Instead, the IPCA said the officers recorded notes after the meetings from memory.
The officers wrote that the piano instructor "told police that he did have an abnormal attraction to children" but was seeking counselling.
A month later, the piano instructor made an application to the Police Vetting Service for a job prospect. The vetting panel used the officers' notes during the process, which the instructor then complained were inaccurate.
The IPCA found that the officers' notes were unsubstantiated and should not have been disclosed by the Police Vetting Service.
The report said the officers should have taken their notes during the visits instead of afterwards.
"There is considerable value in police conducting prevention visits in such circumstances," IPCA Chair Kenneth Johnston KC said.
"However, the fact that the officers took few contemporaneous notes of the visits, and instead recorded from memory what had been said at various times after the event, was in the authority's view poor practice."
Police acknowledged the report's findings.
"The original vetting request has since been withdrawn and subsequently closed by police," Superintendent Shanan Gray said.
"Although we have taken learnings from this incident, police remain confident that the officers acted professionally, in good faith, and had community safety at the forefront of their minds when recording the outcome of this complaint."
Both officers are still working for NZ Police.