Raglan's stormwater is being upgraded but residents are up in arms.
And they accuse Waikato District Council (WDC) of pushing through the upgrade without meeting resource consent requirements.
"Not meeting with the community for two, really three years, and doing what they want to do is a bit 'deviant' in my opinion in that they are abusing Raglan," said Fred Lichtwark from Whaingaroa Harbour Care.
On Friday, concerned environmental groups and iwi met with WDC for the first time in more than two years to express frustration over the system which has been installed.
They believe more modern filtration technologies and systems should have been considered.
"There are lots of options out there," Raglan resident, Malibu Hamilton said to WDC. "Our task is to see that you have got the knowledge in place to see if you can retrofit. There's absolutely no reason why Whaingaroa can't be a leading example of good environmental kaupapa.
"While you say it's running along smoothly, it's not. We don't consider it is and we seek better outcomes for our community."
In response, WDC Water Manager, Karl Pavlovich said the upgrade at Wainui and Stewart streets was needed to diminish flooding effects on nearby properties.
"It also gives us capacity to expand in the future, and that's the proper way to do it in terms of engineering," he said. "Sort out your flows first, then... look at phase two which is now how you mitigate those environmental impacts by adding treatment devices to the system."
Locals want action to protect their beautiful harbour from litter and pollutants like oil and tar which collect on kerbsides and end up on kaimoana beds and on the beach.
"There are devices like hydrocarbon separators, wetlands, grass swales that could be employed," said Lichtwark who is also a Waikato Regional Councillor.
Mr Pavlovich admitted that in recent years, meetings with the community had been missed due to high staff turnover, and the WDC accepted that it had not consulted fully with the community.
He said there had been no recent assessment on the impact of the discharge to the harbour or kaimoana stocks.
But he stressed that WDC is committed to working with locals to find the best stormwater solutions for the environment.
Environmental spokesperson for Tainui Iwi, Angeline Greensill said the meeting was useful and isn't worried about things happening.
"If they don't happen, we just make them accountable. They will happen," she said. "It's just that I wish it happened quicker."