Johannesburg (AFP) – Coca-Cola produces 120 billion throwaway plastic bottles a year, Greenpeace Africa said at a protest in South Africa Thursday, urging the soda maker to use glass and tin packaging to cut back on plastic pollution.

Activists erected a giant bottle cap outside the company's Johannesburg office emblazoned with the slogan "Cap it Coke" in a demonstration held on World Environment Day.

Coca-Cola has been the world's top plastic polluter for six consecutive years, the environmental activist group claimed.

"Coca-Cola produces 120 billion throwaway plastics every year. And most of it will end up in the environment and in the marine ecosystem," Greenpeace representative Hellen Kahaso Dena told AFP.

"So today, we are outside the office telling them to cut plastic production, invest in refill and reuse, and ensure that they are investing in other sustainable forms of packaging such as glass and cans," she said.

The company's claims to be promoting plastics recycling amounted to "greenwashing", she claimed. "We know that only about nine percent gets recycled. Most of the plastic will end up in the environment," Dena said.

The group also urged Coca-Cola to stand behind a push for a Global Plastic Treaty that will prioritise a cap on plastic production.

Negotiations among delegates from nearly 200 nations for the world's first accord on cutting plastics pollution ended without agreement in South Korea last year after opposition from a bloc of mainly oil-producing countries.

A new round is due in Geneva in August.

Since the failure of the talks, Coca-Cola lowered its environmental commitments by effectively scrapping a pledge to reach 25 percent reusable packaging by 2030, and pushing back dates and amounts for recycling goals.

Over 99 percent of plastics derive from fossil fuels, directly linking plastic production to the climate crisis, Greenpeace said.