Police are investigating a sudden death after a body was found in a car submerged in the Whanganui River.
Emergency services were called to the Anzac Parade scene near the Wanganui Motor Boat Club at 11.50am on Tuesday.
One person was found dead in the vehicle.
Following the discovery, Taupo Quay between Wilson St and Berdeck Village was closed for much of the afternoon while police completed a decontamination process in a vehicle.
"Police were concerned about an unidentifiable box in the car that would have posed a gas risk," senior sergeant Neil Forlong said.
The area was later cleared.
"Police will be making enquiries to understand the circumstances of the death," Whanganui area investigation manager senior sergeant Andrew McDonald said.
Police put a cordon up around the scene at the slipway near the Wanganui Motor Boat Club on Anzac Parade.
Hours after a the car was discovered, emergency services blocked off part of Taupo Quay while five fire trucks attending the scene and a Hazmat command unit set up.
Firefighters and police, including detectives, met inside a command unit before firefighters in Hazmat gear took a large bin inside a building next to the command centre before emerging and going through a decontamination wash down.
Three staff at Whitlock Freight were asked to leave their premises behind where the command unit was set up.