Nelson City Council is apologising to residents for the nasty smell coming from its Wakapuaka Wastewater Treatment plant.

The plant is in breach of its resource consent, as conditions state there should be no objectionable odour past State Highway Six.

A spokesman says the smell’s being caused by a changeover of algae in the ponds and record-breaking hot temperatures.

But he also stresses a recent upgrade means this shouldn’t have happened.

Action’s underway to reduce the smell, but the council warns there’s no instant fix.

– NewstalkZB