Distance: 5.0 km (3.5 DOC hours) - Unmaintained track - Hard terrain
Altitude: 414m to 593m. Gain: 99m. Loss: 273m . Gradient: 4 deg (Moderate)
Skills: - Extreme rivers (5/6)

Unmaintained track (5/9)
Former track, overgrown - markers / ground trail still followable

Secondary, unmapped (4/5)
Route not on maps, an alternative recognised access to hut or along range / catchment

Moderate (difficulty: 3/5)
Occasional moderate climbs

Hard (difficulty: 5/5)
Thick scrub-bash / continuous river boulders, waterfalls, or gorges

None (difficulty: 1/7)
No alpine skills required

Extreme rivers (difficulty: 5/6)
Major rivers - likely to be impassible in all but ideal conditions

None (difficulty: 1/7)
No alpine skills required

WOuld be very cold in winter. Can get ice in the river.

Pretty obvious - follow the river. There are several swims and some big rocks to scramble over and around. It'd be very hard going upstream as some large rocks had large drops on the downstream side. Best route if you are confident with river travel and don't mind getting very wet.

Note: Described in the reverse direction to your journey

It would be very hard to travel upstream - there were several large rocks we had to slide down and getting up them would require a lot of effort. But the rivers change so it may be fine.