State Highway 25 between Hikuai and Opoutere is closed from 6pm tonight until 8am, Wednesday, March 8.

Emergency access on the route will be maintained, according to a Facebook post by Waka Kotahi.

In the post, a Waka Kotahi spokesperson says contractors are "cutting into the bank" to textend the road further away from the advancing underslip this afternoon.

"They are keeping traffic flowing as much as possible but periods of stop/go traffic management are required. Road users should expect long delays," the post reads.

"The road will have to be fully closed for a period of time later today while contractors construct the pavement for the road widening.

"The road was originally closed early yesterday morning following a washout caused by heavy rain over the weekend. Ground conditions in the area remain highly unstable. Contractors are constantly monitoring the site to ensure it remains safe, and the road may be closed at short notice should conditions deteriorate further."

Plan ahead for a safe, enjoyable journey. Keep up to date with:

• Traffic updates: http://spr.ly/61863Lpsq

• Facebook: http://spr.ly/61873LpsS

• Twitter: http://spr.ly/61883Lpss

• Journey planner: http://spr.ly/61893Lpst

• Phone: 0800 4 HIGHWAYS (0800 44 44 49)