Motorists are being asked to avoid the area of a fatal accident near Cambridge, in the Waikato

One person has died another is badly hurt after the crash on State Highway One, near the intersection of Hydro Road.

The Transport Agency says a detour's in place.

Acting Waikato system manager, Rob Campbell, says there are a number of events on in the region today, including a rowing regatta at Lake Karapiro.

He's urging people to plan ahead and allow extra time.

Campbell says heavy vehicles should take additional care on the detour route, due to the extra traffic.