A "foreign object" blockage is the suspected cause of a wastewater overflow in Rotorua today.
Signs have been erected in an inner-city stormwater culvert warning people to keep clear of a sewage overflow.
The signs are in the culvert that connects to the Utuhina Stream between Tarewa Rd and the reserve by Mataatua Marae.
A man who lives on Tarewa Rd said he saw two Fulton Hogan trucks used to for sucking up sewage on Tarewa Rd late this morning.
He said he also saw a Rotorua Lakes Council staff member testing the water in the culvert this morning and again this afternoon.
A Rotorua Lakes Council spokesperson said there was an overflow from a wastewater main at Mahoe Street today and some wastewater entered a nearby stormwater drain.
"TRILITY have responded and organised to have the stormwater drain blocked to stop any further wastewater moving through the pipe.
"The stormwater drain was flushed and further downstream two 'sucker trucks' removed fluid from the stormwater drain to ensure any further wastewater didn't reach the Utuhina Stream.
"It is likely that a minimal amount of wastewater entered the Utuhina stream prior to the above actions being put in place."
The spokesperson said Toi Te Ora Public Health had been notified and there were "currently no restrictions in place for the stream or Lake Rotorua".
"Staff are awaiting a report to find out the cause of the overflow. However, it is suspected to be a foreign object (e.g. a towel, a toy) in the pipe which has caused a blockage resulting in the overflow."
Security camera footage will also be examined to determine the cause.
"Blockages often occur when people put things into the wastewater system that they shouldn't. The only thing going into the wastewater system should be toilet paper."
It comes as an iwi group makes a last-minute legal move to stop the works.