Read more: Opua slip repair could take more than two weeks
Big slip blocks highway near Kawakawa
NZ Transport Agency system manager Steve Mutton said the slip had left an estimated 10,500cu m — about 650 truckloads — of loose earth and rock sitting precariously above the road.
Because of the instability of the slip face, in the early stages crews were working carefully from the top down with just one excavator and only in daylight.
"Our aim is to reopen the road as soon as possible given the importance of the link to the Bay of Islands for locals and tourists. But we must take a safety-first approach and, depending on the weather, the road may be closed for another four to six weeks," he said.
So far a geotechnical assessment had been completed, a plan had been devised for clearing the slip and stabilising the hillside, and local iwi Ngati Hine had blessed the site.
In the meantime Mr Mutton urged local residents not to try driving past the slip.
''It's a very unstable situation,'' he said.
Paihia Business Association chairwoman Robyn Stent said the road closure added to what had already been a difficult season for many Bay of Islands businesses.
''We know that the harder it is to get into a town, the less likely people are to come.''
Wild weather had also forced seven cruise ships to abandon their visits so far this summer. Two had made it into the Bay but couldn't offload passengers.
An earlier storm coupled with king tides had swept away chunks of shoreline close to Waitangi Bridge, closing sections of the footpath and affecting businesses there. The waterfront along Paihia Beach was also eroding.
Charles Parker, general manager of Fullers GreatSights, said anything that made it more difficult or time-consuming to get to a place would have an effect on tourism businesses.
His company had not yet seen a drop-off in numbers of people booked each day but many of the bookings had been made before the slip.
It also meant some staff had to travel an extra 20 to 30 minutes to get to work. Some who lived in Kawakawa and worked in Opua were using bikes to get to work via the Twin Coast Cycle Trail.
Meanwhile, State Highway 1 through the Mangamuka Gorge, south of Kaitaia, will be closed for resurfacing for four days starting tomorrow. The road will be open overnight but will close each morning at 8.30am, reopen from 4pm-5pm, and close again from 5pm-8pm.
The closures will continue, weather permitting, until Tuesday. The closure times have been changed following feedback to the original plan, and will allow traffic to get to the A&P Show in Kaitaia on Saturday and home again.
The new times would also allow people using SH1 for school, work and freight to plan ahead, Mr Mutton said. A second closure is scheduled for March 3-6. A detour will be in place via SH10 between Awanui and Pakaraka.