West Coast residents say plastic waste is becoming strewn along their beaches, because councils haven't monitored a landfill near Fox Glacier that spilled into floodwater last March.
The Westland District Mayor is downplaying the damage as "nowhere near" the environmental disaster that some might make it out to be.
After the old landfill split open, volunteers, Defence Force staff and DOC workers removed more than 13,000 bags of rubbish, while Westland District Council temporarily reinforced the landfill with mesh and rocks.
However, it was too late to retrieve other rubbish which washed out to sea or became lodged in the riverbed, including burnt plastic.
A former clean-up volunteer, Des Watson, said this week he had collected about a thousand pieces of that each day at Nine Mile Beach near Westport, more than 200 kilometres north.
"I'm finding a lot of broken, hard, fragmented plastics, a lot of polystyrene, strapping tape, rope, and burnt plastic that's been melted, that indicates it's from the Fox Glacier," he said.
"The other indication that it's come from Fox Glacier landfill is where else would all this rubbish come from?"
He said it had been a disappointing discovery, but if he didn't intervene the brittle plastic would keep getting smashed on the shore into more small pieces.
Watson was concerned it could potentially affecting the local marine life, which includes seagulls, oyster catchers, penguins and seals.
"I just thought there would be some kind of monitoring on our coastline to see the impact of what the unknown amount of rubbish, that had washed out to the ocean from the landfill, was doing to our coastline," he said.
Fox Glacier guide Kelsey Porter said she'd also been keeping an eye on the landfill after helping out with the cleanup last year.
She would like to see much quicker progress from the council to move the landfill to a less vulnerable location, as well as a strategic plan for monitoring rubbish which was unearthing itself from the river after large storms.
"It would be great if they could team up with DOC and have a volunteer list that they could tap into when they needed to do more cleanups," she said.
"Even if it was unrealistic to do it after every storm, they could at least do it twice a year."
However, Westland mayor Bruce Smith said the council was monitoring the riverbed for rubbish, and had applied for government funding to move the landfill as a post-lockdown "shovel ready project".
"But there is a reality, and that is that in some places the rubbish would be a metre under the sand. Our team keep an eye on that," he said.
He didn't believe the rubbish had made it as far as Westport.
"The claims have been made that the rubbish is washing up in Milford, and the claims have been made that the rubbish is washing up in Westport. One is south of us and one is north of us by a considerable distance. I think the chances of there being any substance to that are quite slim."