"The success of this new research not only applies to the Great Barrier Reef but has potential global significance -- it shows we can start to restore and repair damaged coral populations where the natural supply of coral larvae has been compromised."

The scientists used the technique again this November and Harrison said they had already observed successful settlement of the new coral larvae.

"We'll be monitoring the growth of both coral colonies and working to further refine the technique for potentially broader application in the future," he said.

Bleaching

Coral bleaching is a stress response that happens when an increase in sea temperatures causes the expulsion of algae that grow inside coral, turning the reefs white and eliminating their main energy source. It's directly linked to global warming.

Bleaching doesn't kill coral straight away -- if temperatures drop, the algae has the chance to recolonize. But if temperatures remain high, eventually the coral will die, removing the natural habitat for many species of marine life.

Earlier this month, Tourism and Events Queensland released images of the coral spawning this year, an "extremely positive" sign that the reef was recovering.

"Typically it would take previously bleached coral several years to spawn so this is extremely positive news for the reef," spokesman Jarrod Meakins said. Large colonies of a reef-building coral were part of the spawning and it was expected that there would be another spawning event in December, he added.

During the spawning event the coral release trillions of eggs and sperm into the ocean in the hope they find a matching mate to create new coral. The spawning takes place after a full moon with timing also thought to be affected by factors including the length of the day and salinity of the water.

'Soaring ocean temperatures'

UNESCO's report on coral ecosystems, released in June, states that "soaring ocean temperatures in the past three years have subjected 21 of 29 World Heritage reefs to severe and/or repeated heat stress, and caused some of the worst bleaching ever observed at iconic sites like the Great Barrier Reef."

Harrison's research was funded by the Great Barrier Reef Foundation.

'One piece of the puzzle'

The Great Barrier Reef Marine Park Authority's chief scientist David Wachenfeld described the larval reseeding as "one piece in the puzzle" of protecting the reef.

"It is vital everyone keeps working to address climate change and build the Reef's resilience, and for restoration strategies to be developed that can work over large areas," Wachenfeld said.

"The success of these first trials is encouraging -- the next challenge is to build this into broader scale technology that is going to make a difference to the Reef as a whole."

Harrison's team had previously used the technology on a damaged reef in the Philippines, where he said the larvae had grown to "dinner plate sized adult colonies" within three years, with the ability to reproduce.