WRC flow phone 083 225 495 for Whataroa Bridge. Take 40% of this for the Perth River.
If you want more hardcore action take your over night gear, get that dropped at Scone Hut and get flown 2-3 kilometres upstream to the edge of the Wilderness area (helo not allowed beyond this)
From here down it is steep, low volume creeking class IV-V with a couple of crux class V’s (or portages depending on flow.) everything is portagable. If you are doing this you might also want to walk up Scone Creek (about 30mins (don’t follow the track up the ridge and away from river) cut down to the creek and walk up another 300 metres until you get to the bottom of an unrunnable 12m waterfall. The first drop is a clean 4-metre autoboof followed by cool rapids down to the confluence. (you’ll want higher flows for Scone than Upper Perth, but should be good around 1300-1450mm gauge)
To get to the take out: find the Whataroa River bridge on SH6, turn eastwards on the gravel road on the southern side for 2 kilometres to the old bridge site. There is a large parking area, and camping is allowed. Make sure you have a ready stock of insect repellent because the sandflies are rather aggressive.