Great Barrier Reef: $500 million in federal budget to protect icon

The Turnbull government will allocate $500 million in the May budget to help restore and protect the Great Barrier Reef.

But the cash splash has been met with criticism from Labor and conservationists who have accused the government of not doing enough to address the thing that poses the biggest threat to the reef, climate change.

Federal Environment Minister Josh Frydenberg and Foreign Minister Julie Bishop pledged the half-a-billion dollars in funding in Cairns today.

Mr Frydenberg said it was a game-changer that would help secure the reef's future.

"This is the single largest investment in restoration and management in Australia's history," he told the ABC.

Some of the funding will be funnelled directly to farmers to enable them to modify their practices and reduce the amount of sediment run-off into the reef.

Mr Frydenberg said the money would also go towards improving water quality, tackling the crown-of-thorns starfish and scientific research.

"Millions of dollars will go into science and to better data management, and to be able to test the impacts on the reef," he said.

"We are looking at a whole range of new initiatives, taking the best advice of the experts, working closely with the Great Barrier Reef Marine Park Authority to ensure that the reef has its best chance into the future."

But despite the funding, Mr Frydenberg reaffirmed his position that global warming remained the biggest threat to the reef.

Shadow Minister for Climate Change and Energy Mark Butler said the Great Barrier Reef was being attacked "from every side" through climate change, land clearing and trawling.

"You can't be serious about saving the reef without a serious plan to tackle climate change," he said in a statement.

"As long as Malcolm Turnbull continues to pander to the climate change deniers of his party room the Great Barrier Reef will continue to suffer."

Australian Marine Conservation Society spokeswoman Imogen Zethoven said while the funding was welcome, it would be pointless if carbon pollution was not reduced and the Adani coal mine was allowed to go ahead.

"Australia must make the transition from burning polluting coal to a 100 per cent renewable powered future if we are to protect the future of the reef," she said in a statement.

350.org founder Bill McKibben agreed.

"To simultaneously promote the world's biggest coal mine while pretending to care about the world's largest reef is an acrobatic feat only the most cynical politicians would attempt," he said in a statement.

But Great Barrier Reef Foundation Chairman John Schubert welcomed the announcement.

"There is no doubt that our great living treasure is under enormous threat from climate change and we must all work together to do everything possible to achieve the Paris Agreement," he said in a statement.

"But while the world works to tackle climate change on a global scale, there are many things we can and must do to build the resilience of the Great Barrier Reef right now."