A 46-year-old man has disappeared while swimming in the Whanganui River.
Police were notified of the man's disappearance about 2pm at Mosquito Point - a popular swimming spot about 5 kilometres north of Whanganui.
"The man was intending to swim across the river to the opposite bank and jump off a nearby cliff. Family and friends saw him swim toward the opposite bank but then lost sight of him," said Sergeant Colin Wright.
Family members swam across the 50-metre-wide river shortly afterwards but could not find the man.
"Whanganui Coast Guard launched their boat and carried out a shore line and river search. A helicopter has also been used to search from the air and police patrols carried out searches of the river banks on both sides of the river," Mr Wright said.
"We have grave concerns for his well-being and we are speaking with the man's family and friends.
"The search has been stood down for this evening but the Police Dive Squad has been contacted and it is anticipated they will conduct a search of the river over the weekend."