Global public outrage has grown at marine pollution, sparking demands for more recycling and better waste management. Only 9 percent of plastic is recycled, environmental groups say.

Germany, the U.S. and Japan each exported more than one billion kilos of plastic waste last year, U.N. figures show.

There is an estimated 100 million tons of plastic in the world's seas, with eight million tons added annually, the United Nations Environment Program (UNEP) says.

Officials from 187 countries taking part in UNEP negotiations are considering legally-binding amendments to the Basel Convention on waste that would regulate trade in discarded plastic.

The United States has not ratified the 30-year-old pact.

"The dynamics are relatively positive because we see an overwhelming majority of countries supporting tighter control on plastic waste trade," David Azoulay of the Center for International Environmental Law (CIEL) told Reuters at the Geneva talks that end on Friday.

"I have never seen an issue move so fast through the different hurdles than plastics. It is a combination of public pressure, and of the fact that plastic is an easy issue to picture, it is visual compared to most other environmental problems," he said.

Importer consent 

Under a proposal brought by Norway, and backed by Japan and several African countries, shipments of non-hazardous mixed or plastic waste that are not ready for recycling would be added to the list of substances requiring importers' prior consent.

Any plastic that goes on this so-called Annex 2 could not be traded between parties and non-parties to the Basel treaty.

"That would prevent the U.S. from sending - it would only allow the U.S. to export plastic waste that is already sorted, cleaned and ready for recycling," Azoulay said.

"Which is exactly the type of waste they don't send around because it has value."

Though outside of the pact, the United States could ship plastic waste under bilateral deals if the equivalent of environmental standards under Basel are guaranteed, experts say.

Reuters could not reach the U.S. observer delegation for comment.

Single-use plastic items such as straws, forks and knives as well as cotton buds will be banned in the European Union by 2021, following a vote by EU lawmakers on March 27.

China stopped processing other countries' waste in 2017, leading to more plastic waste being diverted to southeast Asia, especially Thailand, Indonesia and Malaysia, campaigners say.

"If this (proposal) passes, it actually improves the regulation on plastic waste trade, it becomes much more difficult to dump plastic waste on developing countries that cannot deal with it and not safely manage it," Eirik Lindebjerg, global plastics policy manager at the conservation group WWF, told Reuters.

The decision should be a "no-brainer and an obvious first step" to controlling waste streams from rich countries, he said.