An Adelaide-designed app enabling mobile phone users to communicate even if their networks fail has won international acclaim at the Pacific Humanitarian Challenge.

Dr Paul Gardner-Stephen of Flinders University created the Serval Mesh app so people in disaster-struck areas could continue to communicate among themselves.

The free app has been described as two-way radio for the 21st century.

It competed against 129 others from 20 countries to win the $279,000 AusAID prize.

Dr Gardner-Stephens said he would use the prize money to trial the app with residents on a remote Pacific island.

How it works

Serval Mesh utilises Bluetooth and wi-fi to transfer encoded messages between neighbouring phones hosting the app.

Primarily, data in the form of SMS, maps and other text files can be moved across the network.

If a direct link is available between phones, a phone call can be made.

"It might take a few seconds or a few minutes depending on the network context to get a text message through to someone else," Dr Gardner-Stephen said.

The Serval Mesh app offers many services normal phone systems do. ( Supplied )

He has also developed mesh extender units to enable the app to work over long distances.

The units receive messages from nearby phones and exchange them to other units using VHF signals.

Much-needed service

Dr Gardner-Stephen said the initial concept was to provide emergency communication systems when traditional phone towers were damaged.

"You don't think about how much you need communications until it is lost," Dr Gardner-Stephen said.

He said the app could also be used to build phone networks in remote and regional areas that do not have service.

An increase in app ownership could then prompt telecommunication companies to install towers.

Dr Gardner-Stephen is investigating testing this use on outlying islands of the Solomon Islands, Fiji or Vanuatu where mobile service is not available.

Dr Gardner-Stephen tests the app at Arkaroola in outback South Australia. ( Supplied: Flinders University )

Serval Mesh is currently available for Android phones only but there are plans for an app to soon be made for iOS models.

"In a typical year, between 100 million and 400 million people are affected by disasters around the world," Dr Gardner-Stephen said.

"If we can reduce and alleviate the suffering and hardship that these events cause, I'll know I've made a really positive impact in the world."