Wanganui District Council will hold a formal meeting next week to discuss ongoing problems with its wastewater plant.
Foul smells started coming from Whanganui's treatment plant before Christmas, after discharges from local companies built up a sludge at the plant to a level which hadn't been expected for 20 years.
The council has been issued with an abatement notice from Manawatu-Wanganui Regional Council because of the odour, which is in breach of the regional air plan.
The meeting will be held at the Council Chambers on Thursday 17 January and the council says formal decisions will be made to try resolve the issue.
Mayor Annette Main says there is a design fault with the plant and it could take months to assess what needs to be done to fix it.