A not-for-profit organisation called Sea Cleaners is collecting hundreds of thousands of litres of rubbish from around the North Island daily.
It's inundated with volunteers wanting to help out, but says it needs more resources to keep up with the demand.
It's only been three months since Sea Cleaners visited the Pahurehure Inlet - and it's already littered with rubbish.
"This is about 45 minutes to an hour-worth of collection here at the mouth of the Pahurehure Inlet. It's bottles, chip packets, car tyres - you name it, we've found it," said Hayden Smith, Sea Cleaners CEO.
Often referred to as the ambulance at the bottom of the cliff, Sea Cleaners is trying to educate people on how to change their habits.
Every day, volunteers jump on board one of its boats to help clean our harbours.
"We've got a vessel working with Watercare on the WaitematÄ [and] Manukau Harbour, as well as Opua in Northland - and [we're] about to launch the next one in the Bay of Plenty," Mr Smith said.
Since they started 16 years ago, Sea Cleaners has removed more than 6 million litres of rubbish from the sea. They've filled 200 shipping containers with loose litter and collected more than 60 million pieces of rubbish.
Earlier this week, a video of a polluted stream on Takanini School Rd in Papakura went viral.
Sea Cleaners usually concentrate on harbours but after seeing the video, they immediately went out and did their best to clean up the stream.
"We just got into it," Mr Smith said. "We used boat hooks, we used scoops, we got in with our hands and just cleaned it up."
That same stream runs into the inlet the Sea Cleaners were working on.
On Thursday, Sea Cleaners collected about 2000 litres of rubbish. Every day there are at least three other boats in other areas doing the exact same thing.
On an average day, Sea Cleaners will collect about 10,000 litres of rubbish.
Mr Smith is urging anybody who sees a piece of rubbish to stop and pick it up.