Dropping into the Waiotauru Valley out of the Akatarawa Forest, this one's named for the old Odlin's milling operation that worked the area. Access is public, open round the clock with no permit or key needed, which makes it a firm favourite with Wellington 4WDers. It can get busy and tight for room on weekends, so be ready to pull over and let others through.

It's a genuine technical track, not one for the inexperienced. Right from the road it kicks off with a climb, then serves up big ruts, steep climbs, large side-angles and heavy bush rash the whole way. Plenty of spots to slide or roll if you get it wrong. A lift and decent mud terrains help, and a winch or recovery gear plus a second vehicle are strongly recommended. It's also a classic for snapping CVs with a heavy foot.

Most vehicles reach the summit, and you can carry on to the Waiotauru hut, though that's harder again. Allow around two hours each way, and bring a sense of humour about your paintwork.