Further evidence that plastic does not discriminate as it spreads across the planet: the marine conservation organisation Sea Shepherd said it is washing up in large quantities on a remote Australian beach.

Sea Shepherd joined Indigenous rangers in picking up more than seven tonnes of marine plastic pollution on a two-kilometre stretch of Djulpan beach, in northeastern Arnhem Land.

Using the same analysis technique employed in a recent study that found a staggering amount of rubbish on the tiny Cocos (Keeling) Islands in the Indian Ocean, researchers have estimated there would have been 250m pieces of debris along the full stretch of the 14km beach.

The clean-up of Djulpan beach, about 2 1/2 hours drive from the township of Nhulunbuy on the western side of the Gulf of Carpentaria, was conducted over two weeks last October. There is no road to the beach. The rangers from Dhimurru Aboriginal Corporation cut a 4WD track through scrub to reach it.

A collection of the bottle tops removed from Djulpan beach during the clean-up. Photograph: Rebecca Griffiths/Sea Shepherd

Liza Dicks, from Sea Shepherd Australia, said it was the worst case of plastic rubbish the group had found in more than 600 clean-up exercises at mainland Australian beaches.

About two-thirds of the debris were consumer items: water bottles, cigarette lighters, ice block wrappers, shoes, thongs, toys and toothbrushes. The rest was 72 types of discarded fishing net, some of which contained turtle bones.

Jennifer Lavers, a marine biologist at the University of Tasmania who led the Cocos (Keeling) Islands study and helped Sea Shepherd analyse what it found at Djulpan beach, said much of the rubbish was single-use and disposable. Some of the plastic appeared to be decades old.

“It is likely this waste came from southeast Asia, but we know at the same time Australia’s waste is going over to somewhere else,” she said.

“It is incredibly commonplace, but for the average ordinary person it’s probably pretty shocking to learn that these remote pristine places have such a high density of plastic. This is not some untouchable thing. It is a thing we can do something about.”

Last month the prime minister, Scott Morrison, vowed to do more to stop Australian plastic ending up in oceans. He won in principle backing from state and territory leaders to boost the struggling local recycling industry and ban the export of recyclable material.

No timeframe has been set for the ban, which will be discussed at a meeting of environment ministers in November. Government data suggests just 12% of the plastic waste Australians put in kerbside bins is recycled.