Google's parent company is set to launch balloons into the Caribbean skies in an attempt to restore telephone networks in hurricane-ravaged Puerto Rico.

Alphabet Inc, which controls Google, obtained authorisation from the US Federal Communications Commission (FCC) to deploy the devices -- developed from 2013 as part of a project known as "Loon."

It aims to temporarily re-establish Puerto Rico's cellular network -- where 83 per cent of cell sites were still out of service Friday, according to FCC figures.

"More than two weeks after Hurricane Maria struck, millions of Puerto Ricans are still without access to much-needed communications services," FCC chairman Ajit Pai said in a statement.

"That's why we need to take innovative approaches to help restore connectivity on the island," he added, urging wireless carriers to "cooperate with Project Loon to maximise this effort's chances of success."

Loon, part of a series of futuristic projects out of Alphabet's "X" laboratory, was originally created to provide internet coverage in under-developed rural areas.

A similar project using drones was closed down in 2016.

The balloons are sent 20 kilometres above the Earth's surface, where they can remain autonomously for over 100 days. They are made from a polyethylene canvas the size of a tennis court. 

Initially designed to drift, the balloons are now equipped with navigation systems, powered by solar panels, which keep them in a specific area.

Source: AFP