This is the northern end of the popular Southern Crossing route to Kaitoke.
Crossing the swingbridge at Otaki Forks, the track starts out broad and gravelled. A short climb leads to retired pastures on terraces above Otaki Forks - a flat and pleasant grassland. On reaching the base of the hill 1km beyond, a track forks left to Waitewaewae and the Otaki RIver, The Field track starts to zigzag up the face, heading generally south. The track remains graveled and broad (it is maintained by dingo / ATV which gives you a clue of the quality) and climbs steadily but not steeply. Vegetation is regenerating bush as far as about the 500m contour, where mature, uncleared bush begins. This is approximately the half-way point.
Once in the mature bush, the graveled track ceases and a standard tramping track begins. That said, it is very well used, and kept in good condition - stone & gravel underfoot with some muddy sections. After a short meander along a flattish spur, the climbs start again - rising another 300m in 2km, in a series of moderately steep climbs to reach Tirotiro knob.
From Tirotiro it is another 1 km on meandering up and down to the saddle where Field Hut can be found.