New Zealand's soft plastics are sitting in storage in Auckland, Wellington, Canterbury and Dunedin.

Well-meaning Kiwis dutifully recycling have instead been contributing to a whopping stockpile of plastic - weighing the equivalent of 66 million single-use bags.

About 400 tonnes of plastic - stored in depots across the country - has been growing since an Australian manufacturer stopped accepting soft plastics collected in our supermarkets this year.

Some of the plastic earmarked for recycling could end up going mouldy while being stored, with only a fraction being processed into reusable items.

Last week, the Government announced single-use plastic bags would be banned within six months, but Bags Not co-founder Nick Morrison said there needed to be more solutions for plastic.

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New Zealand had poor planning and management for plastic, while avoiding the real problem - how to curb the mass accumulation of waste.

Instead, a meaningful resolution was needed, not a band aid solution, Morrison said.

"There's a responsibility that certain industry and government leaders have to take in regard to the predicament we're in.

"Ultimately, we just have to get rid of it. We have to totally change our relationship with plastics."

The gigantic amount of soft plastic - spread across 25 containers - is the plastic people are dropping in special bins at supermarkets for plastic bags, food wrappers and any plastic which can be scrunched into a ball.

Instead of being recycled, it's sitting in storage in Auckland, Wellington, Canterbury and Dunedin.

The Packaging Forum spokeswoman Lyn Mayes said the stored plastic was being assessed for quality.

"What we have found so far is that if post-consumer plastic is stored inside containers for some time, it is likely to go mouldy as any food and liquid contaminants break down."

Mayes said it was the forum's "absolute priority" to find processors for what it collected.

AMY BAKER/STUFF Kiwis are putting soft plastic recycling in the right place in bins at supermarkets, but currently, it's headed for a large stockpile.

Melbourne-based recycled plastic manufacturer Replas stopped accepting New Zealand's plastic at the start of this year.

Since the last shipment was delivered to Australia, that plastic has been stacking up.

Two companies take the soft plastic - Future Post, which makes the soft plastic into fence posts, and 2nd Life Plastics.

The Packaging Forum have said it's supplying Future Post with about one container of soft plastic a month.

Carl Longstaff, chief executive of Metal Art, a Replas NZ licensee, said there needed to be 20 to 30 companies like Future Post to reduce the stockpile.

"It's going to take more than two or three companies to tackle that stockpile", Longstaff said.

ABIGAIL DOUGHERTY/STUFF Bags Not co-founder Nick Morrison said New Zealand's plastic problem needed industry leadership.

The popularity of the scheme meant people would likely continue to put more and more of their soft plastic in the special supermarket bins.

"We've done our own research here. It's too much for one manufacturer," Longstaff said.

The Packaging Forum has tried to find overseas processors for the stockpile, but found they were being fussier about the quality of plastic sent. ​

Instead, Longstaff said there needed to be less plastic packaging in the first place.

MARTIN DE RUYTER/STUFF New Zealand's stockpiled soft plastic, intended for recycling, has amassed to a ginormous plastic stockpile of 400 tonnes.

"If they could reduce their packaging by 50 per cent, then New Zealanders would only be recycling half of what they're currently recycling.

The Packaging Forum was doing the work "after the horse has bolted", he said.

Mayes said the forum agreed reducing the creation of waste was important.

"Soft plastic is a flexible and lightweight barrier protection and its primary role is to protect and preserve products.

"Companies are looking at alternatives including compostable packaging but there is limited infrastructure for this at present."

Soft plastics recycling

2015 - Soft plastics recycling introduced to some New Zealand cities in 2015.

2018 - Melbourne-based soft plastic recycling manufacturer Replas becomes inundated, and stops accepting New Zealand's soft plastic recycling

January 2018 - China stops accepting general recycling from New Zealand, and other countries

September 2018 - Govt announces single-use plastic bag phase-out consultation

November 2018 - New manufacturer Future Post announces it can take some soft plastic recycling

November 2018 - Govt announces single-use plastic bags will be banned within six months, including thicker bags