A decision on when to re-open State Highway 1 through the Mangamuka Gorge would be "worked through" this week, Waka Kotahi NZ Transport Agency Northland system manager Jacqui Hori-Hoult said on Friday.

"There are two slips on the northern side of the gorge that are causing concern, and we want to take a bit more time assessing them and our next steps as to the final repairs required," she said.

"The weather has been good, and we're pleased to see these slips have stopped moving, so that's good progress."

Most of the slips on to the road had been cleared, although there were places where traffic would be reduced to one lane.

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"We are looking at when we can open the road to light vehicles from local communities so they can make essential journeys without having to go via a long detour," Hori-Hoult added.

"Once it's safe to do so, we could let locals through in convoys at set times of day, but the road won't be open to trucks and buses for a while."

The biggest slip was near the bottom of the gorge on the northern side, where the hillside under the road had fallen away. Another had not fallen away, but had caused the road to slump significantly. Trees close to the roadside appeared to be holding the slip in place "for now."

"Both slips are challenging repair jobs so we can't just rush into it. We need to have enough safe room for vehicles away from the slip face to be able to travel past them," she said.

State highway 1 is currently closed between Victoria Valley Rd and Makene Rd, with SH10 providing the detour, adding 20-30 minutes to the journey from Kaitaia to Pakaraka.