As with all the forrestry roads up the North Bank, you are best to check for current access status at the information board just off the highway. At the time of placement this road had been open for a while, and it appears all forrestry work along it is complete so it should be open for some time to come. The road follows a slightly different route to what it used to, and ends a couple of hundred meters short of the DOC boundary. A good condition gravel forrestry road, that you should be able to get up in most vehicles. A ford near the start is probably the biggest obstacle.
From here you can carry on with the walk up Mt Riley and Mt Sunday.