The Wanganui District Council could face Environment Court action after failing to stop the pong coming from its stinky sewage plant.
Horizons Regional Council is preparing to seek an enforcement order from the Environment Court over odours plaguing the facility and wafting over the city.
The foul odour has plagued Whanganui since December, earning it the nickname "Ponganui".
On January 9 the regional council gave the district council an abatement notice requiring it to cease causing an objectionable odour beyond the plant boundary by 5pm on Thursday.
Horizons strategy and regulation group manager Dr Nic Peet said the council's ability to comply with the notice would be assessed over the next few days but the regional council was also preparing for more enforcement action if investigations warranted it.
"While we accept that a lot of work had been carried out by the district council to do this, it is now our responsibility to determine whether or not it is able to comply with this abatement notice," Dr Peet said.
The enforcement order would be likely to result in a jointly agreed action plan, monitored by the court, that the district council would be bound to obey.
Although this would not make the sulphurous stench vanish instantly, Dr Peet said it would give Whanganui residents more assurance the district council was continuing to do everything within its power to resolve the problem.
Whanganui mayor Annette Main said the council was continuing to execute measures recommended by experts to reduce the odour.
Yesterday another 20 tonnes of lime was put on the ponds. The lime drops will continue next week to try to staunch the stench - extra aerators are also being installed to fight the odour.
Gonville resident Veronica McKenna said the pong "went right through" her whole house and hit on Wednesday and Thursday nights.
"The smell makes you feel sick. I can't describe the smell, it's just a stink," Mrs McKenna said.
Last month the council admitted the treatment plant was badly designed and had not worked properly since opening in 2007.
Gonville resident James Wakeling said he "got a whiff" of the stench yesterday morning "but it hasn't been stinking me out".
He said he was not too concerned about problems with the plant, which would be fixed "sooner or later".
- © Fairfax NZ News
What will you be doing on Anzac Day?Related story: Cooper helps RSA to reap poppy harvest