A third round of United Nations negotiations to try to deliver the world's first treaty to control plastic pollution has drawn more than 500 proposals from those involved, participants said on the last day of the talks on Sunday.

Negotiators, who have spent a week meeting in the Kenyan capital at talks known as INC3, have until the end of next year to strike a deal for the control of plastics, which produce an estimated 400 million tons of waste every year.

The plastics industry, oil and petrochemical exporters, including Russia and Saudi Arabia, have said a global deal should promote recycling and re-use of plastic, but environmental campaigners and some governments say much less needs to be produced in the first place.

Environmental group Greenpeace said a successful deal would require the United States and the European Union to show greater leadership than they have so far.

"The hard truth is that INC3 has failed to deliver on its core objective: delivering a mandate to prepare a first draft of a treaty text," Graham Forbes, head of delegation for Greenpeace, said.

"This is not progress. This is chaos," he said referring to the number of submissions.

Two more rounds of talks will take place next year to try to finalize the deal.

Bethanie Carney Almroth, an eco-toxicologist at the University of Gothenburg in Sweden, who was involved in the talks, said delegates were also considering an extra session to analyze the scale of the problem.

"Plastics are connected to climate change, to biodiversity loss and other major threats and crises that we as the human population are facing on the planet," she said.

The United Nations said a statement would be issued later after the talks close on Sunday.

Stewart Harris, a spokesman for the International Council of Chemicals Association, an industry body that favors measures like re-using plastic containers as opposed to production curbs, said the Nairobi talks had delivered ideas that would be whittled down in Canada where the next round of negotiations will be held.

One of the most popular proposals was from Switzerland and Uruguay to hold more discussions on curbing harmful polymers and chemicals of concern.

It had the backing of more than 100 states, said the International Pollutants Elimination Network (IPEN), a global network of non-governmental organizations.

Less than 10% of plastic waste is recycled, the U.N. Environment Program says, while at least 14 million tons end up in oceans every year, the International Union for Conservation of Nature says.

Canada, Kenya, and the European Union are among those who said plastic production needs to be limited, while a coalition of Russia, Saudi Arabia and others has sought to emphasize recycling.

Members of the Saudi delegation at the talks declined to talk to Reuters, while Russian delegates could not immediately be reached for comment.