Releasing the draft proposal, Environment Minister David Kemp said the plan would create the largest network of protected marine areas in the world.

"The Great Barrier Reef is the largest world heritage area in the world and this new zoning system will establish a new international standard for the protection of reefs," Kemp said on public radio.

The plan would expand so-called "high protection zones" from 4.6 percent to around 30 percent of the reef, which covers more than 345,000 square kilometers (133,000 sq miles) off Australia's northeast coast.

These so-called "green zones" areas would be off-limits to fishermen and shipping, with only research and tourism activities allowed.

Other proposals include increasing by one-third the area designated "no-go" zones closed to all users except researchers with permits, and cutting from 50 percent to 34 percent the areas of the reef accessible to prawn trawling.

The draft plan was a result of more than 10,000 submissions from commercial and recreational fishing groups, tourist operators and environmental groups.

Scientists consider the Great Barrier Reef, which consists of some 2,900 coral reefs, 900 islands and 1,500 fish species, the world's largest living organism.

It is also Australia's greatest natural treasure and a key tourism destination.

Environmental groups generally praised the Kemp plan.

But the leader of the Greens party, Senator Bob Brown, said the increase in protected reef areas needed to be backed up with action on land clearing and global warming, which both threaten the coral reefs.

"The reef faces some of its most serious threats from activities carried out outside the reef," Brown said.

"The federal government, by refusing to act on global warming and land clearing, is undermining and will ultimately overwhelm the work being done by the Great Barrier Reef Marine Park Authority to increase protection for the reef."

Coral bleaching already affects half the reef and by 2030 it is predicted severe bleaching events would happen every year unless global warming was addressed, he said.

SPACE.WIRE