Sea urchins could turn pristine reefs in Australia's south-east into permanent wastelands, new international research suggests.

The marine ecosystem study, led by Tasmanian scientist Scott Ling, found sea urchin numbers were increasing in warming coastal waters off south-eastern Australia, because of favourable breeding conditions.

Professor Ling, from the Institute of Marine and Antarctic Studies, warned kelp forests found in eastern coastal waters were at breaking point because of overgrazing by sea urchins.

"When this occurs the kelp beds collapse into these sea urchin barrens," he said.

"You lose all the diversity of species in the kelp bed and you're just left with this barren moonscape."

"One of the things we can try and do is make sure we have a better balance of predators in the kelp ecosystems," he said.

Sea urchins are normally kept in check by predators like rock lobsters, which are worth millions to the state's economy.

Giant kelp forests are threatened by sea urchins. ( Flickr: fiveinchpixie )

Marine ecologist Craig Johnson said overfishing of rock lobsters was also to blame for the rise of the urchins.

"Commercial fishing can remove large numbers of predators from reef systems," he said.

"(We need to make) sure we're leaving some of these predators to perform their role in the ecosystems."

"It's really important, even if you try and rebuild the numbers of predators on these barren areas, it can be really hard, even for predators to drive the urchin numbers down low enough for the kelp to recover."

"It's certainly not a good outcome for the major fisheries, rock lobster and abalone, to be losing these kelp beds, because with a loss of the kelp, there's a loss of production," he said,

Mr Johnson said the rock lobster industry had responded with reduced catch quotas, a limited season and size limits.

"And that cap has been designed for the lobster biomass to rebuild over the next probably five to 10 years."

But the increase in sea-urchin numbers is good news for one part of the aquaculture industry.

Australia's only export-approved sea urchin processing plant at the Bay of Fires has made inroads into the Chinese market, where sea urchins are considered a delicacy.

Scientists hope growing demand sea urchins for the plate could help prevent the collapse of further reef systems.