A leak of information involving returnees staying at Auckland's Sheraton Four Points managed isolation facility resulted in their names, room numbers, and arrival and departure dates being posted to a private Snapchat group.
Managed isolation and quarantine deputy chief executive Megan Main confirmed in a statement those personal details were posted to Snapchat by a First Security guard - which she says is unacceptable.
Main said the security guard posted the image on Saturday morning and it was removed about midday.
"The guard has advised that the image was posted to a private group, and First Security has confirmed the image has been deleted from their phone," Main said in a statement.
"Managed isolation and quarantine staff are responsible for the health, safety, and welfare of everybody staying in our managed isolation and quarantine facilities, and this includes the need to protect their privacy. The investigation into this incident has established the guard had legitimate access to the list, as part of their role processing and monitoring returnees going outside the building for exercise or other reasons."
The photo was of a printed list containing the names, room numbers, and arrival and departure dates of 27 returnees staying at the facility, Main said, as well as the room numbers and names of five staff members.
Main said those actions were unacceptable.
"We sincerely apologise to those people whose privacy was breached," she said. "We have contacted all of those affected to inform them of the incident.
"The guard has been removed from duty at any managed isolation facility and First Security is undertaking an employment investigation. We have expressed our concerns about this incident to the employer."
Main said the Privacy Commissioner has been notified of the incident.
It comes after now-former National MP Hamish Walker leaked confidential COVID-19 patient details last month, claiming he did so to "expose the Government's shortcomings" so they would be "rectified".
A probe into that leak found the Ministry of Health could have protected the confidential information better and that the policy of sending it out should have been reviewed sooner.