The Desert Road will be closed for part of Wednesday morning to allow urgent safety work to be carried out.
The road near the Waihohonu Bridge, on SH1 between Waiouru and Rangipo, is currently down to one lane after a truck crash last week caused extensive damage.
New Zealand Transport Agency spokeswoman Karen Boyt said the state highway would be closed from 7.30am Wednesday for up to an hour and a half while structural engineers carry out a detailed assessment of the damage both on and off the road. This will determine what future repairs are needed.
The second closure, from around 10.30am Wednesday for up to an hour and a half, will allow a temporary barrier to be installed to protect road users. This will enable the road to opened to two lanes.
Boyt said people should be prepared for delays and should use the National Park road if they can.