The United Nations says it is concerned about the state of the Great Barrier Reef and is urging greater efforts to conserve one of the most world's spectacular natural sites.

The decision Wednesday in Bonn, Germany, puts pressure on Australia to prevent further destruction of the 2,300-kilometer (1,430-mile) reef off the Queensland coast.

But UNESCO's World Heritage Committee held off designating the site as endangered, pending further reviews.

Experts say the reef's unique ecosystem is threatened by climate change, waste water, fishing and coastal developments including the use of nearby ports to export coal, which has led to dredging that kills valuable corals.

Australia's environment minister, Greg Hunt, told the meeting that his country had "clearly heard" the committee's concerns and would strive to implement a 35-year conservation plan.