Trees and a few small slips have come down in the Coromandel overnight.
The peninsula is under a heavy rain warning until tomorrow morning, with 140-millimetres of rain expected to fall.
A watch is also in place for severe thunderstorms, which could bring very heavy downpours.
Civil Defence officials are worried about homes in hilly, urban areas - where the small cracks in the land could quickly open up and start to move.
The Thames-Coromandel controller is Garry Towler spoke to Guyon Espiner.
