Scientists in Australia are examining the possibility of enlarging and brightening the clouds around the Great Barrier Reef to save it from bleaching.

Making the low-lying clouds off the north-east coast larger and more reflective could cool the waters below and help to stem the widespread coral bleaching that is occurring with growing intensity across vast swathes of the 2400-kilometre reserve.

Coral bleaching in the Great Barrier Reef in 2016 was the worst on record. Credit:James Cook University

Daniel Harrison, a postdoctoral research associate at the University of Sydney, said preliminary testing indicated that cloud brightening was a "plausible" solution.

"If you're in a hot sunny day and a cloud comes across overhead, you can feel right away there's quite a lot less heat coming through," he told ABC News.