The Transport Agency says it hopes to open a single lane of State Highway 1 at Pukenui in the Far North by the middle of the week.
Torrential rain carved a 20m wide, 5m-deep trench through the highway on Friday afternoon about 40km north of Kaitaia.
It cut the only public road to Cape Reinga.
Drivers in morning and evening convoys under police escort have been using a private forestry road to get round the hole.
The agency said 11 pipes have been laid to form a new culvert under the road.
Police Inspector Chris McLellan will be overseeing the convoy
He told Morning Report the forestry road was in reasonably good condition but it was also used by heavy machinery such as trucks which made passing difficult in some places.
He said about 20 to 30 cars have been in the convoy during each run.