Preparatory talks have begun in the South African city of Johannesburg to try to ensure the success of the international Earth Summit, which opens there on Monday.
Government representatives from about 30 countries are hoping to narrow the differences between developing nations that are seeking more aid and open trade and wealthy ones that want to set tough conditions in return.
The ten-day gathering will have the joint aim of reducing world poverty and curbing damage to the enviroment, but earlier preparatory discussions failed to resolve disagreements on key issues.
Earlier South Africa's President, Thabo Mbeki, called for action rather than words at the Earth Summit.
He said the meeting would have to do more than was achieved at the first Earth Summit in Brazil a decade ago.
Meanwhile in the South African city of Cape Town, at least nine Greenpeace activists were arrested during a protest designed to coincide with the summit.
The activists climbed on to the roof of the country's only nuclear power station and unfurled a banner demanding that Africa be declared a nuclear-free zone.
They had arrived by boat at a jetty beside the power station about 12 miles north of Cape Town.
