Work begins to fix highway slip

The temporary bypass of the slip at Maromaku. Photo / Michael Cunningham

Work to repair a 70m slip on State Highway One at Maromaku will start on Monday.

Flooding in July last year took out a 10m-long chunk, closing the highway in both directions near the Maromaku turnoff for seven days.

The slip forced detours via Mangakahia Rd between Kaikohe and Whangarei.

The NZ Transport Agency has just completed its geotechnical investigations and awarded the 18-week contract to Fulton Hogan.

Agency acting Auckland and Northland highway manager Mieszko Iwaskow said the repair would involve moving more than 3000 tonnes of material to build a stabilised-earth retaining wall with 39 reinforced concrete piles, driven 21m into the ground.

Additional drainage at the base of the retaining wall to help stabilise the slope would be installed.

The highway will be rebuilt along the existing alignment and barriers installed to improve safety.

"We will need to reduce the highway to one lane to complete some of this work but these closures will be limited to the weekend to minimise any disruption to travellers," Mr Iwaskow said.

The cost of the project is $2.2 million.