Global warming has driven ocean temperatures up, leading to three mass bleaching events on the reef since 2015.
A report by the United Nations Educational, Scientific and Cultural Organisation (Unesco) stated "there is no possible doubt" the world’s biggest coral reef system off Australia's northeast coast was "facing ascertained danger."
It is recommending that the 2,300km reef be put in the list of "in danger" sites at the world heritage committee meeting next month. It also says Australia's 2050 reef plan should be revised to take urgent action on the threat of climate change.
The Australian government is resisting the recommendation. Environment minister Sussan Ley said she and foreign minister Marise Payne had called the Unesco director-general to express the government's "strong disappointment" and "even bewilderment."
She said the government was “stunned” by a “backflip on previous assurances” by UN officials.
She said the world heritage committee was “not the forum” to “make a point” about climate change. In the past, "in danger" status has been recommended to sites after effects from armed conflict and war, pollution, poaching and uncontrolled urbanisation.
This is the second time the reef has faced being put on the "in danger" list, with the last time being 2015.
Unesco said key targets on improving water quality had not been met by Australia.
Its report on Monday reads: “The plan requires stronger and clearer commitments, in particular towards urgently countering the effects of climate change, but also towards accelerating water quality improvement and land management measures.”
The country is also facing calls from conservation groups to commit to a target of zero net carbon emissions by 2050.
Australia’s greenhouse gas emissions targets have not changed since 2015.
Ley said on Tuesday: “This decision was flawed and clearly there was politics behind it, and that has subverted the proper process."
She added: "It hasn't even used the latest data. We've got Australian Institute of Marine Science data coming out that's showing really strong work in the recovery from the bleaching events that have occurred. We've got traditional owners managing Crown of Thorne starfish. We've got science, we've got a restoration and adaptation program."
She said there were more than 80 world heritage properties that Unesco had identified as under threat from climate change, but the reef was singled out