Drive south along State Highway 1 to the Paremata roundabout. Take the road to the Hutt Valley.
Alternatively, take the Grays Rd route from Plimmerton. Both end up in the same place if you follow the signs to the Hutt Valley.
Once you have come over the Haywards Hill (by the power station), turn left at the traffic lights.
Then, follow the directions as if you were coming from Wellington.