A drone rescued two swimmers off an Australian beach on Thursday, a world first for the fast-developing technology that seems perfectly suited to saving lives at sea, authorities said.

The rescue took place as life savers at Lennox Head, a beach popular with surfers south of the city of Brisbane, were preparing for a training session on using drones to pull swimmers to safety.

The practice turned into a real rescue when someone noticed that two men swimming outside safety flags were in trouble in a three-metre swell, the government said in a statement.

Lifeguards launched the drone, steered it toward the swimmers and dropped a "rescue pod" into the water, where it expanded so the swimmers could grab it and swim to shore.

Rescued in 70 seconds

"Never before has a drone fitted with a flotation device been used to rescue swimmers like this," said John Barilaro, the deputy premier of New South Wales state.

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Lifeguards launched a drone (not pictured), steered it toward a pair of struggling swimmers off an Australian beach and dropped a "rescue pod" into the water on Thursday in the first rescue of its kind. (Peter Parks/AFP/Getty Images)

The rescue took just 70 seconds. The two swimmers were exhausted but unharmed.

Barilaro said the state government had invested about $427,000 Cdn in a trial of drone technology in December.

Australia, most of whose 24 million inhabitants live on the coast, had 291 drownings in the year to June 30, a small increase over the previous year but a decline on a per capita basis, according to the Royal Life Saving Society.