State Highway 30 near Benneydale is blocked after a truck rolled and brought down powerlines just before 1pm on Wednesday.
The highway is currently closed at Mangaokewa Road and is expected to remain blocked for the next couple of hours.
A local detour is available but motorists are advised to take an alternative route.
The driver of the truck received minor injuries.
The Lines Company said 55 customers have lost power due to the crash and crews are working to restore it.
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