A plan to let prisoners have Skype video-chats with family members has been scuppered before it began, because officials couldn't guarantee the security of the personal data of criminals and their families.

An in-prison trial of the online video-chat software, which allows computer users to talk and see each other using webcams, was due to take place in November.

The trial was sparked by the closure of New Plymouth Prison, and was intended as a way to help prisoners stay in touch with family and friends even if they had been relocated to a prison out of the region.

Department of Corrections lower north regional commissioner Karen Petrie said approval for the trial was withdrawn after the project team identified "a number of risks that could not be mitigated", in particular the security of prisoners' and their families' personal information when sent via the internet.

As an alternative, private video-conferencing facilities between Whanganui Prison and the New Plymouth Service Centre are being used.

Managing prisoners' communications with the outside world has often caused headaches for prison authorities.

New Zealand prisons routinely use radio signal jammers to prevent inmates using illicit mobile phones, but even sanctioned communications can be problematic.

In 1998, career criminal Arthur Taylor used a prison payphone to arrange his so-called "dial-an-escape" from Auckland Prison in Paremoremo.

He had permission to call 10 pre-vetted phone numbers, but he arranged for one of those numbers to be signed up to a Telecom call-divert service, from which he could call any number in the country.

He used those calls to plot an escape for himself and three others, and later phoned the television current affairs show Holmes from behind bars. Taylor was also alleged to have found ways to access the internet from within prison.

Rethinking Crime and Punishment director Kim Workman said it was a shame the Skype trial had been cancelled as prisoners were being made to serve their time further away from their families, and some visitors couldn't afford to travel to visit in person.

"We've got to use the technology much more effectively than we are. Prison services are being centralised, so prisoners are some distance away from their families."

Last year email was trialled for prisoners at the drug treatment unit of Wellington's Rimutaka Prison.

Only inbound email from friends and family was allowed, and prisoners had to reply via regular phone calls or post. Emails were screened for inappropriate material before being passed on. During the three-month trial, 76 emails were received, and the service is still available in the unit.

Petrie said the aim of the trial was to establish whether inbound email increased support for both prisoners and family and friends.

Other benefits included the potential to reduce prisoner self-harm by maintaining connections outside of prison, increased support for foreign prisoners, and a cheaper way for people to stay in touch.

"We remain committed to ensuring that prisoners maintain their relationships with their friends and family members in the community."

A recent review of publicly accessible computer systems revealed inmates at Auckland's Mt Eden Prison had gained limited access to external websites - one of 12 security breaches identified among government agencies.

According to media reports, the Scottish Prison Service is currently considering using computer technologies such as Skype to improve communications between prisoners and their families.