SYDNEY • Australia's iconic Great Barrier Reef will die unless radical climate action is taken, including phasing out coal-fuelled power, the Sydney Morning Herald reported on Saturday, citing a report by a government agency.

The reef will collapse if the planet warms by another half a deg C, according to a private report prepared by the Great Barrier Reef Marine Park Authority - the government's lead agency for managing the reef - and obtained by the Herald under freedom of information laws, the paper said.

Australia is blessed with natural wonders such as the Great Barrier Reef, but its economy remains reliant on mining and fossil fuels.

Political inaction has made climate change a key election issue as Australians prepare to head to the polls on May 18.

While neither the incumbent Liberal-National coalition nor main opposition Labor party has committed to phasing out coal, Labor is targeting emissions cuts and a greater reliance on renewable energy.

The agency's report says limiting the average global temperature increase to 1.5 deg C or below since industrial times began "is critical to maintain the ecological function of the Great Barrier Reef", according to the newspaper, and the world has already warmed by one deg C.

Scientists have said that coal must be phased out within three decades to avoid the 1.5-deg C threshold, the newspaper reported.

Climate change has already wrought devastating effects on the World Heritage-listed reef, the paper reported, including two consecutive years of mass coral bleaching in 2016 and 2017.

BLOOMBERG