"This is a large slip, approximately 2000 cubic metres of material has come down and our contractors have been working hard to clear it and get the road open again.
"The helicopter will help bring down any unstable material above the slip. Once this is complete, concrete barriers will be installed and one lane will open to traffic under stop/go traffic management so drivers can get through.
"At this stage we expect to have one lane open this evening. However, people will experience delays of five to 10 minutes due to the traffic management onsite."
Stop/go traffic management will remain in place until the site is assessed as safe to fully reopen.
Another update will be sent out at 5pm today.
For personalised information about driving conditions on their frequently used routes, motorists can check out and sign up to On The Move at www.onthemove.govt.nz
For real time information on highway conditions and incidents, or to report issues on the network, visit www.nzta.govt.nz, call 0800 4 HIGHWAYS (0800 44 44 49) or follow the Transport Agency on Facebook or @nztawaibop on Twitter.