"I don't want to sentence one today and have the other point the finger at him at a later date.''
Greene and Isabeth travelled behind the victim's rental van while driving from Hokitika to Greymouth.
Angered by the manner in which the rental was being driven they followed the van into central Greymouth, and ultimately up a dead-end street.
Greene then ran to the van, wrenched open the door and started punching the driver about the head. When the tourist asked, "What have I done wrong?'' Greene said: "You nearly f.....g killed us.''
As he continued the attack, Isabeth struck the victim once with the hammer, leaving puncture wounds on his right hand, left forearm and right inner thigh with one strike. Greene then delivered more punches, wrenched the keys from the ignition and threw them up the road before driving off.
The tourist told police the hammer used in the attack was covered in white powder and the hammer found in Greene's van was not only covered in white powder but had fresh blood on the head.