Diversions are in place after a serious crash near Pokeno and Mangatawhiri in the Waikato.

The crash has closed State Highway Two just east of the intersection with State Highway One, Bombay.

Diversions are in place along Koheroa Road and Island Block Road.

Heavy motor vehicles must use Island Block Road or other suitable routes.

Police are encouraging motorists returning to Auckland from the Coromandel or Bay of Plenty to either delay their journey, or use alternative routes away from the crash.