A Kawerau resident has described the smell wafting over the town from a nearby worm farm as like "pungent, raw sewage".

Mike Burrell is one of at least 37 residents who have complained to Bay of Plenty Regional Council over the past 10 days through its pollution hotline.

He says the foul odours are coming from Ecocast Vermicast Waste Solutions plant, which processes sewage about 2.5km north-east of the town centre.

An inspection has found the worm farm operation to be non-compliant with resource consent conditions.

"The whole town's had a gutsful," says Mike.

"I was talking to a young woman who was pregnant down at the supermarket and she was dry retching. Everyone could smell it. It was wafting through the mall entrance. It's disgusting. The town demands immediate action, today."

While residents say the smell has been worse over the past two weeks, Mike says the smell has been noticeable in town for years.

"This has been going on too long. It's more prevalent when you're closer to it, obviously, and whenever the wind comes through town it's pretty fierce and its unmistakable. Enough already. How much more do they want us to tolerate?"

He has been told the worm farm did not require public notification or consultation.

"They don't need to consult the public. That's where it fails right there. We don't even get to put in a submission in regards to having a s... farm anywhere near our town. We don't even have a say in it. It's just a real slap in the face," says Mike.

The plant on McKee Road is the largest worm farming operation in New Zealand. It was started by former Kawerau District Council operations and services manager Tom McDowell as a small operation and was incorporated in 2007.

By 2021, it had grown to 10 hectares and now covers 24 hectares. Every year it processes upwards of 40,000 tonnes of biosolids from several Bay of Plenty council wastewater systems.

The biosolids, which would otherwise be sent to landfills, are blended with waste wood pulp fibre from local mills and placed into windrows in fields, where it sits for 18 months while worms go to work converting it into vermicast.

Grass and other green plants grow on the top of the windrows. This is mown and worms process the clippings along with the other waste products.

The end product is then tested for safety before being sold as fertiliser.

Another Kawerau resident, who did not want to be named, says it's "a bit like a farm smell but stronger".

"It's been quite warm and muggy in Kawerau recently and you go to open the window to get a breath of fresh air and the wind comes through and it's got this horrible smell in it."

She says the smell has been coming and going irregularly over the past two weeks.

"I think it's because the wind has been coming in our direction. One day It could be smelled all through the shopping centre. You come out of New World and you get a mouthful of the smell. You walk around Ranfurly and Jellicoe Court and you just can't get away from it."

She says someone put the Pollution Hotline number on a community Facebook page so she rang through.

"The guy that I talked to was quite helpful. I don't know what they can do about it but I hope they can do something."

The regional council's acting compliance manager Trudy Richards says a compliance officer visited the site on Tuesday and found it to be non-compliant with its resource consent for discharges to air.

"The officer found uncovered windrows that were likely generating odours and confirmed non-compliance.

"We are working with site staff to improve their management practices and odour mitigation in accordance with the resource consent, and further compliance action is being considered."

Ecocast manager Tom McDowell was approached for comment and says he's working with the regional council to resolve the issue.

Trudy says the council encourages the community to report any offensive odours or other pollution incidents to its 24-hour Pollution Hotline on 0800 884 883 at the time that it occurs.

LDR is local body journalism co-funded by RNZ and NZ On Air.