His family found his car on Rangiora Rd yesterday morning.
Mr Metcalfe said search and rescue volunteers and locals in one of the boats located the man's body upstream or about 2km from where he had parked his car at 11.55am.
Two police officers then left by boat and retrieved his body.
Mr Metcalfe said it was not unusual for people to go floundering alone.
"At this stage, we're unsure what happened to him. He did all the right things by saying where he was going and when he'll be back," he said.
"He was a fit man, a strong swimmer and at this stage we're trying to ascertain what happened."
Police have withheld the man's identity until his family is officially informed of his death.
Ten people have drowned in Northland so far this year- twice as many as at the same time last year.
Northland's drowning rate is the highest in the country and Water Safety New Zealand has urged everyone to be more responsible around water.