New developments in search and rescue could save lives.

A search and rescue device that creates an area of mobile phone coverage beneath a search helicopter might save lives, proponents say.

Vodafone and Police Search and Rescue recently tested a prototype of the Search and Rescue Network in the Hunua Ranges.

The device creates a temporary cell phone network, giving rescuers on board helicopters the ability to communicate with cell phones below.

Though it isn't ready for operational use yet, Auckland Search and Rescue coordinator for Police Sergeant Dene Duthie said the new technology could prove to be a lifesaver in the future.

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"It is very exciting to have a two way communications system in a zero coverage area that actually lets us communicate directly with a missing person," he said.

"There have been a number of cases in the past where technology could have saved us time, money and potentially lives. We are looking forward to this going further."

The Search and Rescue network would be compatible with both national and international SIM cards.

The helicopter's altitude determines the size of the mobile coverage area. At 300 metres above ground the coverage area is up to 4.5 square kilometres, while at 100 metres it reaches 1.5 square kilometres.

The idea was first floated after American tourists Rachel and Carolyn Lloyd were rescued in the Tararua Ranges in May 2016.

The mother and daughter had been missing for several days before a rescue helicopter spotted their 'help' sign laid out in rocks on the ground.

Vodafone Technology Director Tony Baird said it was like "creating a searchlight across the bush using a mobile signal."

"After watching the Lloyd's story we figured there must be a way Vodafone innovation could help SAR (Search and Rescue) teams locate missing people faster," he said.

"We're really keen to keep working with SAR to get this technology to a stage where it could be used in real life search and rescue operations."

Though the network has been tested successfully, Vodafone said further tests were required before it could be deployed in real life rescue operations.