It has been a big job to do, with contractors working 5 metres below the road level on a sandy base, which has made the work tricky and has had safety challenges.
Altogether 11 pipes which are 2.1 in diameter have been laid to form a new culvert under the road and the stream has been diverted to run through the pipe,NZTA's Northland System Manager, Jacqui Hori-Hoult, said.
Backfilling is now well under way to cover the pipes up to road level. About 5,000 cubic metres of material is needed to fill the gap left after the washout created a hole about 20 metres long and 4-5 metres deep.
"The conditions on site and difficult access have meant progress has been slower than anticipated. There is no overnight work for safety reasons, but work will resume at first light tomorrow," Ms Hori-Hoult said,
"The Transport Agency understands the closure is frustrating and we thank people for their continued patience and understanding, especially towards our road crews on site as they work to reopen the road.''