The Whakatikei River run is short but intense when in high flood. The Hutt River needs to be very high (>= 3m on Te Marua Gauge) for the Whakatikei to be "on". Enter a small side stream at the end of Bulls Run Road and pick your way past the trees etc and enter the Whakatikei after approx 1km. Don't rush - try to play a bit as you paddle down or it will all be over before you realise. After 2-3km of class II+ the gradient picks up with approx half a km of good class III rapids which are boat scoutable. On entering the Hutt River be aware of the extra power of the main stream as it thunders into the walls at the confluence. Paddle across the Hutt River and take out at Poets Corner on river left.
Make sure you keep a good eye out for logs.
As far as I know, the section above the one described here should contain some class II-III water but has not yet been run by any current local paddlers. Access to the upper section is difficult. There is a possibility that GWRC may dam the Whakatikei for water supply.