The Desert road is closed from Waiouru to Rangipo and a detour is in place after a serious crash.
Southbound traffic can use SH46 and SH47 to National Park, left onto SH4 to Whanganui then left onto SH3 to Bulls. Reverse for northbound.
The NZ Transport Agency says given the amount of holiday traffic on the roads the detour will add approximately 1.5 hours to a journey time.
It says the road is expected to be closed for some time so people should avoid the area if they can or check before they travel.
Road users can get the latest by calling 0800 4 HIGHWAYS or checking the website: www.journeys.nzta.govt.nz/traffic/
They can see alerts for their journey at: www.journeys.nzta.govt.nz
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