The Corrections Department will have another crack at using GPS technology to track offenders on home detention and parole.

It will investigate the use of ankle bracelets with built-in GPS transceivers, which would make it easier to locate offenders on the run.

The department trialled an earlier generation of the technology in 2006 that required a separate GPS unit. But the 20 test units, costing $160,000, have been gathering dust for two years.

They were designed to be carried by offenders when they left their houses, and receive regular radio signals from their ankle bracelets so an alarm could be triggered by the unit if an offender left home without it or dumped it.

It was thought the units could also trigger alerts if offenders approached or travelled somewhere they shouldn't, such as schools or parks. But patchy satellite coverage and accuracy problems meant Corrections did not go ahead with a wider rollout.

The fact that offenders could ditch the units also meant that they could not be tracked if they fled.

Community probation manager Katrina Casey says the equipment is "currently held in storage".

Corrections and electronic monitoring provider G4S New Zealand will look at options from February, she says. "It may be that there have been some advances in the technology available since 2006 that could improve the viability of GPS monitoring in some circumstances.

In particular, GPS would be more reliable if the technology could be integrated with the bracelet rather than separately.

"We are aware that work is well advanced on this front."

The department has signed a 32- month contract with G4S worth between $10 million and $12m.