Australia's Trade Minister Andrew Robb says US president Barack Obama's suggestion Australia isn't doing enough to save the Great Barrier Reef is misinformed and unnecessary.

Mr Obama piled pressure on the Abbott government to act on climate change while in Brisbane for the G20, saying natural wonders like the reef are under direct threat.

Foreign Minister Julie Bishop says her office has now sent Mr Obama a briefing on federal government preservation efforts, but stopped short of rebuking him.