A dispute between an uncle and his nephew in Havelock North on Saturday evening ended with one being treated for stab wounds and the other in a police cell.
Hawke's Bay Police Inspector Matt Broderick said police were called to the scene in Panckhurst St about 6.35pm after the wounded man, aged in his 60s, had gone to a neighbouring house to call police.
The man was said to be bleeding heavily from several stab wounds to his arm and back.
Mr Broderick said it was not immediately known what had sparked what he described as a "family dispute" but that it had "quite clearly, seriously escalated".
Police went to the home of the nephew, which was understood to be nearby, and arrested him a short time later.