Countries can reduce plastic pollution by 80% by 2040 using existing technologies and by making major policy changes, the United Nations Environment Programme (UNEP) said in a new report on Monday.

The Kenya-based UN body released its analysis of policy options to tackle the plastic waste crisis two weeks before countries convene in Paris for a second round of negotiations to craft a global treaty aimed at eliminating plastic waste.

The report focuses on three main market shifts needed to create a "circular" economy that keeps produced items in circulation as long as possible: reuse, recycling and reorientation of packaging from plastic to alternative materials.

"If we follow this roadmap, including in negotiations on the plastic pollution deal, we can deliver major economic, social and environmental wins,” said Inger Andersen, UNEP executive director.

The treaty negotiations, known as INC2, will take place from 29 May to 2 June and are expected to result in key inputs for the first treaty draft, which needs to be done before the third round of negotiations in Kenya in November.

UNEP estimates that government promotion of reuse options like refillable bottle systems or deposit return schemes could reduce 30% of plastic waste by 2040.

It also says recycling could achieve an additional 20% by that year if "it becomes a more stable and profitable venture" and fossil fuel subsidies are removed, and that the replacement of products like plastics wraps and sachets with compostable materials could yield an additional 17% reduction.

Countries have different approaches to tackling plastic waste. Some major plastic producing countries like the United States and Saudi Arabia prefer a system of national strategies.

Some that have formed a "High Ambition Coalition," comprising Norway, Rwanda, New Zealand, the European Union and others, have called for top-down approach where global targets are set to reduce virgin plastic production and eliminate fossil fuel subsidies, among other measures.

Some campaigners said the UNEP blueprint fell short of tackling the root of the pollution problem.

"A treaty that does not cap and reduce plastic production will fail to deliver what the people need, justice demands, and the planet requires,” said Angel Pago, director of Greenpeace's plastics campaign.