The Prime Minister and other world leaders arriving in Rio tomorrow (local time) must intervene to strengthen the farcically weak text agreed by bureaucrats today, said the Australian Greens.

"Twenty years after making laudable commitments to sustainable development, which spawned three international conventions, the world's diplomats have taken no steps forward and are failing the needs of this planet and future generations," said Australian Greens environment spokesperson Larissa Waters, from Rio.

On the eve of the United Nations Rio+20 conference, marking 20 years since the Rio Declaration on Sustainable Development, a new report commissioned by Australian Greens has found Australia is failing all of the environmental commitments it signed up to 20 years ago.