A robot submarine able to hunt and kill the predatory crown-of-thorns starfish devastating the Great Barrier Reef was unveiled by Australian researchers on Friday.

Scientists at Queensland University of Technology (QUT) said the robot, named the RangerBot and developed with a grant from Google, would serve as a "robo reef protector" for the vast World Heritage site off Australia's northeastern coast.

The RangerBot has an eight-hour battery life and computer vision capabilities allowing it to monitor and map reef areas at scales not previously possible.

"RangerBot is the world's first underwater robotic system designed specifically for coral reef environments, using only robot-vision for real-time navigation, obstacle avoidance and complex science missions," said Matthew Dunbabin, the QUT professor who unveiled the submarine.