A slip the size of a shopping mall has the Manukau City Council imploring people to stay away from Kawakawa Bay.
Five houses below the slip and one above the slip, which is moving, have been evacuated.
The council says security guards are in place to stop people getting close to the slip and the road below it will remain closed for at least the next month.
About 1500 people living in the east coast area have to take an alternative route to Auckland city, which adds an hour and a half to the journey.
For this reason, economic director Rick Walden says the council is starting a ferry service from Kawakawa Bay to Pine Harbour marina on Monday morning.
The council is running an additional bus service and Mr Walden says it's considering long-term alternatives, such as building a new road.
Mr Walden says measurements are being taken to establish the speed at which the slip is moving, but it is accelerating.
He says it's impossible to know when the hillside might collapse and it's imperative that people stay well away from the area for this reason.
The council on Friday blocked vehicle access to the area and removed workmen from the site for their own safety.
It also expressed concern about people walking along the foreshore road despite warnings to stay away.
It says the hillside looks deceptively calm but is very unstable.
The council expects the road to be closed for up to a month.