State Highway 1/Desert Road will close for two short periods on Wednesday morning while urgent safety work is carried out.
The road near the Waihohonu Bridge is currently down to one lane after a crash on Tuesday last week caused extensive damage.
The state highway will 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 be opened to two lanes.
An NZ Transport Agency System Management spokesperson, Karen Boyt, says people should be prepared for delays and should use the National Park road if they can.
“We understand the inconvenience this closure may cause and we'd like to apologise in advance for any disruptions.
“The damage to the bridge is extensive and we need to complete this work to keep the public safe.
“Once the work is finished we should be able to open the road to two lanes while we look at what other repairs need to be carried out."
A temporary speed limit will be put in place near the crash site because of the reduced lane widths on the bridge.
The Transport Agency is asking people to drive carefully and abide by all traffic management in place.
NZTA encourages people travelling along the Desert Road to check its website on the day as things may change on site and we will be seeking to open earlier if possible.
Details of SH1 Desert Rd closure
• First closure from around 7.30am Wednesday up to 9am for a detailed damage assessment.
• Second closure from around 10.30am Wednesday until up to 12pm for the installation of safety barrier.
• People should use the website to determine when the road has closed: http://www.journeys.nzta.govt.nz/traffic/
• People should use an alternative route such as State Highway 49, 4 and 47.
• The detour could add up to 40 minutes to a journey.