A drone was used in the rescue of two swimmers off an Australian beach this morning, in a world first for the fast-developing technology that seems perfectly suited to saving lives at sea. 

The rescue took place as life savers at Lennox Head, a beach popular with surfers south 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 teenagers swimming outside safety flags were in trouble in a three-metre swell. 

Lifeguards launched the drone, known as the Westpac Little Ripper, and steered it towards the swimmers and dropped a "rescue pod" into the water, where it expanded so the swimmers could grab it and swim to shore.

The rescue took just 70 seconds.

The swimmers, 16-year-old Monty Greenslade and 17-year-old Gabe Vidler, were unharmed from their ordeal, apart from showing signs of fatigue. Little Ripper Group chief operations officer Ben Trollope said two teenage girls who were on the beach raised the alarm before lifesavers kicked into gear.

"They made the phone call to Surf Comm who radioed our guys and it was just a co-ordinated effort after that," he said.

Within 35 seconds of lift off, the SOS flotation device had been deployed.

"A flotation device was dropped and it inflated within a few seconds, they grabbed it and the waves pushed them in on it."