Civil Defence says a slip on the North Shore in Auckland was an accident waiting to happen.
It cites a history of land subsidence in the area and has questioned why the council allowed houses to be built in Lingham Crescent, Torbay.
Lingham Crescent was cordoned off on Wednesday.
One house is almost destroyed, three are badly damaged and 12 others have been evacuated.
Full tests are expected to be done on Thursday on the stability of the ground, but the results will not be known for a few days.
Earthquake Commission insurance manager Lance Dixon says engineers are draining water on-site to see whether the land can be stabilised.