A model of giant fish made with plastic bottles is exhibited at Botafogo beach in Rio de Janeiro June 19, 2012.

In the swim of things … fish made from plastic bottles are displayed at Botafogo beach in Rio. Photo: Reuters

NEGOTIATORS in Rio de Janeiro have claimed success after finalising a statement to be issued by more than 100 world leaders who arrive in the Brazilian city over the next few days.

But many observers said the ''success'' at the United Nations conference was possible only after the agreement was watered down so far it became meaningless.

''Rio has turned into an epic failure. It has failed on equity, failed on ecology and failed on economy,'' the executive director of Greenpeace International, Kumi Naidoo, said.

The World Wildlife Fund executive director, Jim Leape, said the document was a ''colossal failure of leadership and vision''.

And the Oxfam spokesman Stephen Hale said the world leaders should ''start again''.

But the Brazilian External Affairs Minister, Antonio Patriota, said the result was ''very satisfying … because it is a result. As of yesterday we were facing considerable difficulties to have a text at all''.

And the US chief negotiator, Todd Stern, said the agreement was a ''good strong step forward''.

Brazilian negotiators conceded that the European Union, often a leading force at such negotiations, had taken a far weaker role due to its unfolding financial crisis.

The European Commissioner for Climate Change, Connie Hedegaard, said after the deal was struck ''nobody in that room was happy, that's how weak it was''.

The Prime Minister, Julia Gillard, arrived in the former Brazilian capital yesterday, with her schedule including bilateral meetings, including with the UN secretary-general, Ban Ki-moon, and a formal presentation to the conference today, in between contributions from Turkey and the Ivory Coast.

After running late into Monday night, the 49-page agreement was finally clinched on Tuesday, ready for agreement by the leaders.

It states the world should negotiate new ''sustainable development goals'' by 2015, but could not agree even what themes they should cover.

It states the world should ''take urgent action on unsustainable production and consumption'' but says nothing about how that should be achieved.

And the meeting failed to meet the hopes of environmental campaigners, and the Australian government, that it would at least launch a negotiation for new rules to protect the high seas, outside the boundaries of individual nations' 200-kilometre territorial zone.

That proposal was blocked by Canada, Japan, Russia and Venezuela. Mr Stern denied the US had contributed to its failure.

The ''high seas alliance'' of 25 environmental groups that lobby on the issue said the result was ''profoundly disappointing''.

And a proposal to improve UN environmental decision making was also dramatically watered down. Instead of the prospect of a new UN environmental decision-making body, the agreement defers to the general assembly to decide whether the existing structures need an ''upgrade''.

Mr Naidoo said Greenpeace would have to give up on international negotiations and move to a campaign of civil disobedience to try to overcome the state parochialism that was stopping any progress in multilateral talks to address environmental problems.