Targeting net zero by 2050 wouldn't be enough to slow the rising ocean temperatures to protect the Great Barrier Reef (GBR), a new report from Australia's Climate Council said on Monday.

The report, released by the climate change communications organisation, said if emissions continue at the current pace, coral bleaching could occur every two years by 2034 and annually by 2044.

"Already at around 1.1 degrees of global warming, we see tropical coral reefs suffering an enormous amount of damage," research director at the Climate Council and one of the authors of the report, Simon Bradshaw, told Xinhua news agency.

"The Great Barrier Reef has had massive bleaching events a number of times now in close succession, with very little time for the reef to recover. If warming rises to over 1.5 degrees, then it may be impossible for tropical coral reefs to survive," he said.

"It's definitely too late to get to the actions we take now this year through the 2020s."

The report found 2021 was the warmest year on record for the world's oceans and the 2,300-km World Heritage site could not survive under those conditions.

"If the Great Barrier Reef is in this much trouble, it means that coral reefs worldwide are in a lot of trouble," Bradshaw said.

To avoid a climate catastrophe and best protect the Great Barrier Reef, the Climate Council recommends Australia triple its efforts and take bold measures to reduce its national emissions 75 per cent by 2030, and reach net zero by 2035.

As a first step, the Australian government should match key allies and commit to halving emissions this decade, the report said.

"It's very clear that the world as a whole needs to half emissions this decade. And for a wealthy developed country like Australia, we have to be going further than that," Bradshaw said.

The report came as a UN reef monitoring delegation touched down to assess the condition of the Great Barrier Reef.

The monitoring visit comes ahead of a World Heritage Committee meeting in June, which will consider listing the Reef as "in danger".

Surface waters off southeastern Australia are currently warming at nearly four times the global average, leading to changes in the distribution of species, species collapse and a decline in biodiversity.

Bradshaw said the new recommended scale of action is achievable, "if we're to give the Great Barrier Reef a fighting chance".