State Highway 2 is closed to northbound traffic at Silverstream following a serious crash between a car and motorcyclist.

A motorcyclist is in a critical condition after a serious crash in Upper Hutt.

Police said the crash happened between Western Hutt Rd and Moonshine Hill Rd in Silverstream about 4.45pm on Monday.

The crash involved the motorcyclist and a car.

A police spokeswoman said the motorcyclist was taken to Wellington Hospital in a critical condition.

State Highway 2 was closed to northbound traffic at the intersection with Fergusson Drive following the crash but has since reopened.