Immigration New Zealand says several of its staff have been accused of misusing client records in the past year, prompting at least seven internal investigations.
A spokesperson says 10 complaints have been made about staff accessing client records without authorisation, involving nine staff members.
Four staff have received final written warnings, disciplinary action is underway with a fifth, and another person has resigned.
A further three cases are being investigated.
The acting deputy chief executive of Immigration New Zealand says in all cases except one complaints have been made internally about staff looking at client records when they should not have been.
Steve Stuart says these are deliberate and conscious decisions by people to breach the code of conduct and to access areas of the system where they shouldn't be.
"They're being nosey, really - which is not part of their job and they don't need to do that."
Mr Stuart says Immigration New Zealand was alerted to most of the breaches through an internal audit system or staff members, showing there is a move within the organisation's culture to stamp out the behaviour.