DIVE operators will aim to use their share from half a billion dollars in commonwealth money to cull more crown-of-thorns starfish from the Great Barrier Reef.

The Federal Government has announced $500 million to help restore and protect the reef - the largest single government investment in the Great Barrier Reef in history.

Other funding will go towards improving water quality, tackling the crown-of-thorns starfish and more scientific research.

Former Queensland governor Penelope Wensley, chairwoman of the government's Reef 2050 advisory committee, told reporters in Cairns on Tuesday more money would still be needed to safeguard the natural wonder for the future.

"We will need more, and I'm looking at the (Great Barrier Reef) Foundation because this is a big job,” she said.

"I'm looking to the foundation to help us leverage more money - including from the community and the international business community - to build on this magnificent base announced today to take the Barrier Reef to the very forefront of world attention and protection of coral reefs.”

The coral-eating crown-of-thorns starfish are considered by scientists as one of the worst biological threats to the reef, blamed for 42per cent of coral decline.

To date, the Association of Marine Park Tourism Operators and Reef and Rainforest Research Centre control program has eliminated 750,000 of the starfish from key reef tourism sites in four years.

But the program has been criticised by some scientists and media as being a waste of time and money due to the sheer number of starfish.

Federal Environment Minister Josh Frydenberg acknowledged it was a big task.

"There is still millions of crown-of-thorns starfish left,” he said.

"The work we're doing with this new money will make a significant impact.”