That's one of the findings from new research by the Waste and Recycling Industry Association (WRIA) based on waste audits at Auckland's Material Recovery Facility (MRF) in Onehunga. It makes for uncomfortable reading.
We visited the MRF recently to see the issue first-hand. The facility handles recycling from across the Auckland region and is almost entirely automated. Once material is on the conveyor, there's very little opportunity to intervene.
For commercial premises, contamination is a particular risk. Unlike a household bin that affects one address, a poorly managed office or building recycling stream can compromise an entire collection load. Your recycling reflects your systems and right now, Auckland's systems aren't working well enough.
The good news is that most of the problems are fixable. And fixing it doesn't require a sustainability strategy overhaul. This is one of those areas where SBN members focused on deeper transformation can also make immediate, tangible impact, getting the basics right while pursuing the bigger changes that matter.
What we saw at the MRF
The Auckland MRF is the largest recycling facility in the country, managed by Re:Group on behalf of Auckland Council. It processes recycling from 550,000 households across the region. The scale of the operation makes manual sorting largely impossible. The facility runs on automated sorting technology, with only one point in the process, the pre-sort, where staff can physically intervene.
The most visible problem on our visit was straightforward: recyclables arriving in plastic bags. Staff pull these off the conveyor and send them straight to landfill. There's no way to assess what's inside, and opening unknown bags poses genuine safety risks like glass and sharp or hazardous materials. If it arrives bagged, it's landfill. No exceptions.
What's actually going wrong
WRIA Executive Director Barney Irvine says about two-thirds of contaminated material is unrecyclable, where people treat the recycling bin as a second rubbish bin. This includes items like stones, nappies and textiles. The other third is more frustrating: material that could have been recycled, but arrived contaminated or packaged incorrectly.
"A lot of this is people trying to do the right thing, but not really knowing how. Confusion about recycling rules is still widespread," says Barney.
For businesses, that confusion multiplies across every staff member, every cleaner, and every floor of a building. It's a systems problem as much as a knowledge problem. That means it responds to management.
What to do in your workplace
The most impactful changes are structural, not motivational. Knowing what to do is only half the equation. Your bins and processes need to make it easy to do the right thing.
Remove bin liners from recycling bins. Recyclables go in loose. A liner bag gets pulled at the pre-sort and everything inside goes to landfill with it, regardless of what's in it.
Treat soft plastics as a separate stream. Bubble wrap, shrink wrap, packaging film and plastic bags don't belong in mixed recycling. They tangle in sorting machinery and cause shutdowns. For businesses generating significant volumes, there are commercial collection options. Talk to your waste provider about them.
Brief your cleaning team directly. Cleaning staff are typically the last people to handle bin contents before collection. A brief conversation or a printed guide in the cleaning cupboard is worth more than a company-wide email that gets ignored.
Put the rules at the point of decision. A laminated guide above the bin showing what goes in, and what doesn't, removes the need for anyone to guess. Accepted materials for mixed recycling are: glass bottles and jars, paper and cardboard, plastic bottles and containers (numbers 1, 2 and 5 only) and tin, steel and aluminium cans.
Keep hazardous items out entirely. Batteries and gas canisters in recycling bins cause fires at MRF facilities. These need to go to dedicated drop-off points
SBN Impact Investor WM NZ has a practical guide for business customers worth sharing with your team. It includes a useful rule of thumb: if you're unsure whether something is recyclable, put it in general waste rather than risk contaminating an entire load.
The bigger picture
WRIA is calling for a large-scale national recycling education campaign, funded by central government, something that was promised but hasn't yet been delivered. Until that happens, businesses that get this right have a real advantage: your recyclables actually get recycled.
It's also worth knowing that contamination costs more than just the environment. Rejected loads mean the cost of collection is wasted and businesses may face additional charges depending on their waste contract.
If you haven't reviewed your recycling setup recently, now's a good time. A quick walk-through of your bins, a conversation with your cleaning contractor and a guide on the wall can make a genuine difference.
Check out Auckland Council's free recycling resources.