Contractors prepare to fix slip on SH4 in Parapara

Preliminary work is needed before a large slip on SH4 between Whanganui and Raetihi can be repaired. Photo / supplied

The timeline for repairing a large slip on State Highway 4 between Whanganui and Raetihi is stretching out.

The slip, between Otoko Pā and Kakatahi School, was caused by a storm.

In order to repair it contractors need to re-open a 300m earlier stretch of SH4, downhill from the current highway, NZ Transport Agency systems manager Ross l'Anson said.

Re-opening that requires consent from both Horizons Regional Council and Whanganui District Council, because the work involves moving earth and will be in or near waterways.

Once that old stretch of road is re-opened the repair above should take six to eight weeks, though weather could cause a delay.

The repair might also take longer if bank stability is less than expected once the slip is cleared.