An unsuccessful search for a swimmer who went missing on Sunday afternoon in the Whanganui River has resumed today.
A rāhui was placed on the river after police were alerted to a possible drowning about 1.20pm on Sunday.
Police, ambulance and a helicopter crew were all involved in the search for the swimmer after they failed to surface.
Emergency services were called to a site near Upokongaro.
Police said on Sunday the search has been suspended for the day but is expected to resume Monday morning with the assistance of the Police National Dive Squad.
A rāhui has now been placed on the river between Hipango Park through to the river mouth, according to the Whanganui District Council.
Police Search & Rescue along with Coastguard were working to locate the person, police said.
"We have just been advised that a rahui has been placed on the Whanganui River. This covers the area from Hipango Park through to the river mouth. No further information is available at this time."
A St John Ambulance spokeswoman said the service was notified of a "water incident" at the river, close to Papaiti Rd, at 1.22pm.
One road ambulance crew had been deployed along with a rescue helicopter crew from Palmerston North.
The ambulance crew were stood down but the helicopter had stayed to assist police. By 3.15pm both the ambulance and helicopter crew had been stood down, she said.
A reporter at the scene said the turn-off to Mosquito Point, a popular swimming spot, had been cordoned off. The rescue helicopter could earlier be seen flying back and forth along a section of the river.
Fire and Emergency NZ was also called to the scene but declined to comment as the incident was in the hands of police.