welcome... i have no first-hand experience with tires for this truck, since i have yet to replace any on my PF. there are a couple tires that people generally recommend. for relatively light off-roading i would probably tell you to look into a good all-terrain tire. nothing too agressive, where your on-road drivability will suffer. BF Goodridge All Terrain T/A KO comes to mind.
also, have you checked on the
PCOA? its an austalian forum for pathfinder owners... you may get a better idea of what is locally available for you.
~mike