More than 200 cellphones have been seized each year in prisons since jamming technology was put in place to stop inmates from illicitly contacting the outside world.
Prison authorities say prisoners "spend large amounts of their time attempting to subvert our security systems" and keep obtaining cellphones in the hope they will work, despite the blocking technology.
The jamming devices were introduced in December 2009 and 644 phones have since been confiscated from inside prisons, according to figures released to the Herald under the Official Information Act.
Of those, 72 were seized from inside the maximum security Auckland Prison at Paremoremo, New Zealand's toughest jail. A further 155 were found in the Spring Hill facility in North Waikato and another 160 in Rimutaka prison, near Wellington.
David Linstrom, in charge of technology in the Corrections Department, said blocking cellphones was one tool to stop "many of New Zealand's most dangerous and antisocial individuals" from organising more crime from behind bars.
While jamming technology was in all 19 New Zealand prisons, he conceded the systems are not designed to "provide full site coverage but are directed to the designated prisoner-accessible areas".
"While jamming technology restricts cellphone use, some prisoners spend large amounts of their time attempting to subvert our security systems and continue to obtain cellphones anticipating they might work," said Mr Linstrom.
On any given day, around 8600 prisoners are in custody and Mr Linstrom said there were thousands of movements - between prison, court or police facilities - as well as personal visits from lawyers, family and friends each year.
"While searches are undertaken every time a prisoner enters prison, and after every visits session, all these contacts represent an opportunity for contraband introduction."
Auckland lawyer Davina Murray is facing criminal charges of smuggling an iPhone, cigarettes and a light to a high profile killer in Mt Eden prison.
She has pleaded not guilty and says her 80 visits over 9 months to Liam Reid, sentenced to preventive detention in 2008 for the rape and murder of Emma Agnew, was to help prepare an appeal against his convictions.
The number of confiscated cellphones was not recorded by Corrections before December 2009.
But a high profile drugs case - conducted before jamming technology was introduced - revealed how inmates used cellphones to conduct business with one another.
Detectives in Operation Web bugged the phones of dozens of prisoners at Paremoremo, Spring Hill, Wanganui, Wellington and Christchurch.
The phones were also used to call China to organise the smuggling of pseudoephedrine to New Zealand, which was then manufactured into methamphetamine.
Among those convicted for running the P ring was Arthur Taylor - recently successful in appealing a smoking ban in prisons - and King Cobra leader Rocky Pulete.