A stretch of State Highway 5 near Tarawera will be reduced to one lane for several weeks as roading contractors battle to contain and control both a slip face and a roadside flood-prone stream.
Last Sunday night, around 8.30pm, a major slip along a stretch contractors had been working on sinceApril crashed down and blocked both lanes of the highway.
It was re-opened a few hours later to one lane, but the last of the debris was not removed until 10am Monday.
It occurred on the same stretch as a major slip three months ago.
"We had been in the process of cutting back (the bank) even further to secure long-term stability," New Zealand Transport Agency acting regional highways manager Gordon Hart said.
"Then this one came down."
He said work crews in the area now had a major job ahead of them.
"It is an on-going challenge and this stretch will still be subject to a single lane for the next month while we wrestle with it."
The slip zone is about 4km north of the Tarawera Tavern.
Mr Hart said as well as cutting the slip-face bank back contractors also had to address the issue of the stream's path.
During flooding three months ago it had seriously cut into the roadside bank.
The agency had been working with local iwi on how to tackle the problem with the stream and the work would revolve around shifting its path beside the road and "armouring" it against future flooding.
Police have advised motorists using SH5 to stick to the signposted speed restriction through the slip zone and treat the area with extra caution.
The works would likely add between five and 10 minutes to the journey between Napier and Taupo.
