A body has been found in a river in Northland's Dargaville amid a search for missing man Saxzin Steedman.

Steedman, 22, had been missing for three weeks, after last being seen leaving Cranley St on June 30 about 4pm.

Detective Senior Sergent Shane Pilmer, Northland CIB said police teams found a body in the Wairoa River at 12.15pm on Thursday.

While formal identification was still underway, police believed the body was that of the missing 22-year-old.

"Family members have been informed and are being supported by police," Pilmer said.

The formal identification process was underway, and the man's death had been referred to the Coroner.