Wanganui District Council will have to get resource consent to continue discharging wastewater to the sea.
Phrases such as "raw sewage" and "public health" were bandied around at the Horizons Regional Council meeting at Dudding Lake this week.
A delay in upgrading the Wanganui wastewater treatment plant means it will not be working by its December 2015 deadline, Horizons chief executive Michael McCartney said.
Construction has been delayed because Wanganui District Council is worried the plant is unaffordable.
It is the refusal of two big Wanganui industries to pay what the council wants for waste treatment that is making the upgrade unaffordable, Horizons chairman Bruce Gordon told Tuesday's meeting.
The current delay doesn't qualify as an emergency and continued discharge of untreated waste to sea will now need formal consent.
Mr Gordon said Wanganui District Council had presented Affco and Open Country with a bill to treat their waste.
"They told council exactly where to stick it and they would do their own treatment."
But Wanganui Mayor Annette Main said Mr Gordon had "got it wrong" and that her council was "working really well" with the city's big industrial trade waste users and Horizons on the options for the new treatment plant.
"We are delaying the build because we need certainty about the quantity of sludge production and the cost of disposal before advancing the project.
"We are concerned that the sludge disposal and operating costs of the plant may be unaffordable for everyone in our community, including businesses and households."
Ms Main said council was working with the wastewater advisory group (which includes Affco and Open Country Dairy) to develop a charging regime which was affordable to all users.
At the Horizons meeting, Mr McCartney said the regional council, as environmental regulator, had been "quite accommodating" in giving Wanganui 15 to 18 months to get the upgraded plant going. Time would be up in December 2015 and the council didn't believe the upgrade would be working by then, he said.
Wanganui would have to lodge a resource consent by March 30 to make the discharge legal. Lodging the consent could trigger a national policy statement test. "Untreated effluent can't be discharged to sea, perhaps. It might need some treatment," Mr McCartney said.
Since January this year all Wanganui's wastewater has been screened to remove large particles and pumped to an outfall 1.7km off South Beach. Wanganui District Council has to monitor the effects at beaches and the outfall weekly.
No problems have been found at beaches, but Cr Gordon McKellar was worried about effects on fish caught offshore. He said there should be warning signs, for example for people fishing with Kontiki from South Beach.
"It's in the direct path of raw sewage."