The Wanganui wastewater treatment plant has been partially shut down this week after residents complained of excessive odours.
The district council says the five-year-old plant's aerators were shut down on Tuesday and are likely to stay that way for the rest of the week.
Kaitoke resident Grant Gaisford says he was forced to stay inside with the windows closed because of the strong rancid smell.
Council's infrastructure manager Mark Hughes says a major intake of protein material came through the Beach Road pumping station on the weekend.
He says that material stopped the bacterial breakdown of waste and caused the excessive odour.
He says the plant will get back up and running once the protein material can be treated.
