During a two-hour clean up two weeks ago, a crew collected six bags of nurdles.

Environmentalists have accused a plastics manufacturer of spilling thousands of "nurdles'' into Wellington Harbour.

Nurdles are raw plastic beads used to produce plastic goods. Large amounts of them have been found on some Wellington beaches recently.

IML Plastics, which is based in the harbour-side Lower Hutt suburb of Seaview, is being blamed by beach clean-up crews as a source of the plastic pellets.

THOMAS MANCH/STUFF A handful of nurdles - plastic beads used for manufacturing - found on Wellington's beaches.

The company says any spillage is minimal and a solution is being worked on. Stormwater filtration devices are due to be installed after the manufacturer's plastic lids were found at the nearby Seaview shoreline in May.

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But Petone Beach Clean Up Crew co-ordinator Lorraine Shaab was critical of the company's commitment to cleaning up its nurdles.

THOMAS MANCH/STUFF Petone Beach Clean UP Crew organiser Lorraine Shaab, left, and Wellington Sea Shepherd co-ordinators Michael and Mandy Coleman, are concerned that raw plastic beads are being spilled into Wellington Harbour through the stormwater system.

On Sunday, she captured pictures of nurdles scattered outside IML's factory.

"They were all in the yard, they were under the fence, they were all outside by the pallets, and they were down the driveway. They were everywhere."

Three handfuls of nurdles collected from the ground amounted to more than 850 in total, she said.

SUPPLIED Petone Beach Clean Up Crew organiser Lorraine Shaab was shocked to find thousands of nurdles - a raw plastic material - scattered around the property of IML Plastics in Seaview on Sunday.

"I could have kept going ... this was so blatantly obvious, I didn't have to look for it. So what measures do they have in place?"

Thousands of opaque nurdles, like those used by IML, have washed up on Evans Bay beach, which runs along Welliongton's Cobham Drive.

Sea Shepherd co-ordinator Mike Coleman, who organises a monthly clean up of the beach, said IML Plastics had long been considered a source.

SUPPLIED Petone Beach Clean Up Crew organiser Lorraine Shaab captured images of nurdles left outside the IML Plastics factory on Sunday.

During a two-hour clean up two weeks ago, Coleman's crew collected six bags of nurdles.

Marine research organisation Algalita South Pacific was also concerned after seeing nurdles washed by the rain into stormwater drains outside "a number" of businesses.

Director Raquelle de Vine, who was last week collecting data for an upcoming study on pollution in Wellington, said 40-year-old research showed a high-concentration of the pellets had long flowed into the harbour.

SUPPLIED IML Plastics has been subject to scrutiny in the past, when blue lids washed up on the Seaview shoreline.

"Essentially, it's an oil spill. Just a different form."

IML Plastics manager Richard Jorgensen said filtration devices were on the way and he would reinforce with staff the importance of cleaning up spilled nurdles.

"It's possible that when a truck is being unloaded there is a bag with a tear in it. The policy then is that we clean up that. But sometimes it is not possible to clean it all up," he said.

THOMAS MANCH/STUFF Nurdles among the debris on Evans Bay beach, off Cobham Drive in Wellington.

"We might get 99 per cent of it or 95 per cent of it, but if there are weather elements in play – rain and things like that – by the time you're sweeping it up they are floating away."

It was possible a very small quantity of nurdles reached the harbour through two council-owned stormwater drains nearby, he said.

IML had purchased the filtration devices for those drains, and was waiting for the council to install them.

THOMAS MANCH/STUFF Evans Bay beach in Wellington is one of the worst in the city for plastic pollution.

"If any of it does go down, it's going to be caught by those litter traps."

Hutt City Council trade waste manager Gordon George said the company was proactive about cleaning up mess and was keen to pursue a solution.

"We've got two devices to go in to the drains and, when we get the right size, that will be fitted and that will give us quite a good trial."

The devices may be used in other problem areas if successful, he said.