A third round of United Nations negotiations in pursuit of 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.

Some said the number of submissions represented progress, while campaign group Greenpeace said it was "chaos".

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 tonnes 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.

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.

The International Pollutants Elimination Network (IPEN), a global network of non-governmental organisations, however, said the proposals reflected the robustness of the Nairobi talks.

Two more rounds will take place next year to try to finalise the deal.

IPEN said one of the most popular proposals was from Switzerland and Uruguay to hold more discussions on curbing harmful polymers and chemicals of concern, which had the backing of more than 100 states.

Less than 10% of the plastic waste is recycled, the U.N. Environment Programme says, while at least 14 million tonnes end up in the ocean 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 and Saudi Arabia has sought to emphasis recycling.

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