Negotiations on a global treaty on plastic pollution are being blocked by oil-producing countries and getting bogged down in a "dialogue of the deaf", sources at the talks told AFP on Thursday.

Ten days of talks on finalising an international, legally-binding accord opened on Tuesday amid optimism from organisers that a deal could be done to tackle the scourge of plastic rubbish and microplastics trashing the planet.

But by Thursday, after countries had staked out their positions, the mood had darkened, negotiating sources said.

The “Like-Minded Countries” (LMC) group, chiefly comprising oil-producing states, is opposed to any targets for limiting plastic production.

Rather than drifting towards common ground, “positions are crystallising”, an observer from a non-governmental organisation told AFP after attending discussion groups, where the technical articles of the treaty are being thrashed out by negotiators.

Written documents submitted by nations to the UN negotiations website, consulted by AFP, confirm that Saudi Arabia, the Arab countries group, Russia, Iran, Kazakhstan and Malaysia reject binding measures on cutting plastic production.

Most of these countries want the petroleum origin of plastic to be left outside the bounds of any eventual treaty, and want the agreement to focus solely on what happens downstream, such as waste collection, sorting, recycling.