"Staff assessed that the landslip and the potential for ongoing instability means there is an imminent threat to four houses _ one on Allandale Rd and three neighbouring properties on Motu St."
It appeared the landslip originated on the Allandale Rd property following recent heavy rain, he said.
"The risk means that we have no choice but to issue dangerous building notices, which will remain in place until the properties can be made safe."
The notices meant the properties could not be used, he said.
"Clearly this will be extremely distressing for the occupiers of the properties, especially right before Christmas.
"We are advising the owners and occupiers to talk to their insurance company.
"However, we will be assisting with emergency accommodation if required," he said.