The United Nations Educational, Scientific and Cultural Organization (UNECSO) says the Great Barrier Reef should be put on a list of endangered world heritage sites.
But Australia stands against such moves.
A meeting on the issue is set for next month.
The BBC's Shaimaa Khalil reports from Sydney.
The UNESCO recommendation has sparked anger from the Australian government, with the Environment Minister Sussan Ley saying Australia would strongly oppose it.
She added that officials were stunned by what she described as a backflip on previous assurances by the U.N. that this step would not be taken.
The UNESCO report says despite efforts and achievements by the state and federal governments in Australia, key targets on improving water quality in the reef had not been met.
If the recommendation is followed, it would be the first time a natural world heritage site has been placed on the endangered list mainly because of impacts from climate change.
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