Once a year after a full moon, a coral reef gets its annual shot at reproduction thanks to an underwater "snowstorm".

This year, the sex life of coral on the Great Barrier Reef has more spectators than normal.

"Swimming around in a soup of egg and sperm is a unique experience, something I would encourage everyone to do if you have the opportunity," dive instructor Tony Fontes said.

The Whitsundays are the first islands in the world to be a part of a scaled-up "coral IVF" program, where tourism operators work alongside scientists to increase the chances for propagation.

Over the course of a week, coral spawn was collected for fertilisation in floating larvae nursery pools.

The fertilised larvae were then taken and released in concentrated doses to a damaged reef off Hook island where it is hoped new life will thrive.

Coral "sexpert" Peter Harrison from the Southern Cross University pioneered the technique, after decades of field work taught him the popular understanding of coral reproduction was wrong.

"Most corals don't reproduce by producing lots of little larvae in their polyps and releasing them," Professor Harrison said.

"They actually produce lots of eggs and sperm and release these during spawning events."

By collecting the spawn, Professor Harrison said they were enhancing the natural process.

"In most cases, during the week-long development of the larvae, most drift away from the parent reef and end up drifting out into the ocean and don't actually contribute to the next generation," he said.

With high success rates for the first four years of research and trials on the Barrier Reef, Professor Harrison is hopeful the scaled-up approach will continue to see similar results.

A world-first

Plans to expand coral IVF is one of the Great Barrier Reef Foundation's ongoing projects, with managing director Anna Marsden saying it was particularly close to her heart.

"That's why we're getting a helping hand from the local community and tourism operators who are helping us collect as much spawn as possible, because essentially every piece of that is a coral baby."

Mr Fontes has watched changes on the reef for over 40 years and said the community was buzzing due to the opportunity to contribute.

"The scientists have created a technique that is definitely something that we lay people can manage with their training," he said.

"At the end of the day, cost is important, and when tourism operators can do it as volunteers with minimal cost, then it's a project that can continue on and scale up, and that's the beauty of getting Whitsunday tourism involved."

The importance of 'underwater cities'

The ability to regrow coral reefs is hindered by the time it takes for coral to reach maturity, with some taking up to 10 years to be of breeding age.

But Ms Marsden hopes that communities the length of the Barrier Reef will be participating in coral IVF within the next five years.

"Coral reefs are the lungs of the seas and are important underwater cities for so much of the marine life that we love," she said.

"So it's really important we're able to rebuild these underwater cities at the same pace we're losing them, [and] at the moment we've been falling short."

Mr Fontes is also concerned about the wider, long-term issues impacting the reef.

"Because all the baby corals we put out there won't survive coral bleaching any better than the corals that preceded them."

But to be a part of the annual coral spawn is a special experience not lost on the long-time diver.

"I'm not a coral sex therapist, yet they've got it wired. I'm just an outside observer, which sounds kind of weird."