Prisoners are getting their hands on mobile phones, despite the item being contraband in all New Zealand prisons.
Photos showing Auckland South Corrections Facility inmates posing and showing off their tattoos have popped up online.
Corrections confirmed to 1News that the surfacing photos had led to "extensive searches".
Five cell phones have been found hidden at Auckland South Corrections Facility since January 2017, with each provided to police for forensic examination.
Chief custodial officer Neil Beales told 1News Corrections became aware of the photos in May this year.
"The phone used was not found, and intelligence information concluded that it had been disposed of," Beales said.
Images of inmates have been posted online as recently as July 6.
Beales said they have asked for the images to be taken down from social media but it was difficult to meet the high threshhold that warranted the removal. He said they used an extensive range of methods to prevent contraband entry.
"These include extensive perimeter security, camera surveillance, searches of staff, contractors and visitors, and their vehicles, scanners and X-ray technology; specialist detector dog teams (including dogs that can detect cell phones) and prisoner telephone monitoring.
"Technology is rapidly advancing and we are always working to stay ahead of offenders' attempts to manipulate our security processes."
Corrections Association President Alan Whitley told 1News that new, tiny cell phones the size of a finger known as "beat the boss" phones were increasingly being sought by prisoners. Their tiny size meant they are more easily hidden internally.
"I know Serco found one of these a little while ago," Whitley said.
"Phones are an issue in all prisons ... we are forever trying to find ways to beat them."
Labour Party corrections spokesman Kelvin Davis believed contraband was still easily being smuggled in and some Corrections Officers were complicit in that.
"They [Corrections] don't seem to be focusing on the issue of corrupt Corrections Officers, spoiling it for the good Corrections Officers, making his colleagues unsafe," he told 1News.
"It's almost like protecting the reputation of Corrections is more important than the safety and the transparency of the system."