Horizons councillor Greg Cox has written an open letter to his colleagues asking them not to sock Wanganui ratepayers with a huge fine for the problems with the city's wastewater.
Smell from the crippled wastewater treatment system has been drifting across the city on and off for weeks.
Mr Cox said Wanganui District Council could be fined hundreds of thousands of dollars if the odour continued.
The council has already received a warning from Horizons Regional Council last October and an abatement notice on January 9.
The next step could include a court appearance, fine and prosecution but council chief executive Michael McCartney said that was unlikely.
"An offender doing their best to fix the problem is unlikely to get a hefty fine," Mr McCartney said.
A fine would not be fair on ratepayers, Mr Cox said, because it was councillors and council staff that caused the problem.
He has been following a paper trail of evidence about why the system isn't working and said he can't believe officers and councillors went ahead with the wastewater system.
It hadn't delivered anywhere near its intended design since it was commissioned in 2007, he said.
At that stage it was 19 per cent effective.
Last year it was 43 per cent effective.
He said the council was supposed to put in a report on it every year, but there has been none for three years.
In 2009, an expert who saw the plant warned that it was catastrophically wrong. The city would be lucky if the system could be fixed. Mr Cox advocated putting the pile-up of smelly, half-treated waste out to sea.
Mr McCartney said that could be allowed, under emergency works provisions, but only if it was part of a long-term solution and not a regular occurrence.
Mr Cox's fellow Horizons councillor for Wanganui, Bob Walker, said Horizons should fine the people involved in setting up and commissioning the system for their "lies and suppressed information".
Wanganui isn't alone with its wastewater problem. Within the Horizons region there have been recent problems with systems at Raetihi, Ohakune, Mangaweka, Feilding, Halcombe, Sanson, Rongotea, Kimbolton, Dannevirke and Palmerston North. And there had alsobeen problems in other centres. In Napier, two tanks being constructed for a new treatment system are to be covered to contain odour.
"It's my personal view that there should be a regional or national body who oversees the construction of these things to ensure Wanganui and other centres don't end up with the same problems," Mr Walker said.
Big infrastructure, such as wastewater treatment plants, was failing in many places in New Zealand, Mr McCartney said. Councils had under-invested, systems were old, and standards were now higher.
The problems were biggest where populations and industrial waste had also increased.
The fact that Wanganui's was a new system rather than an old one raised some questions, Mr McCartney said.
The city was in another distinctive situation. Its discharge to sea was not complying with its resource consent, but it was also not causing a huge environmental problem that affect people's daily lives.
The smell problem was another matter, with a serious impact on people day to day. Horizons was taking action on that because the plant breached air regulations. Many complaints were made, mainly to Wanganui District Council.
A Horizons staff member now patrols the area two days a week, and Mr McCartney said staff could be deployed within an hour if things escalated.