Northland residents are being urged to plan for extreme storms, floods and tsunamis.
Civil Defence Emergency Management (CDEM) said the large number of rural homes in the region would potentially hamper recovery time from storms and floods.
Northland has been hit hard by floods in recent years, with two major deluges in 2010 causing tens of millions of dollars worth of infrastructure damage.
CDEM senior programme manager Graeme Macdonald said heavy rain and flooding were the most common hazards facing Northland.
"The major storms occur every four or five years and they can be quite severe. Rural homes can be quickly isolated in an emergency, so they need to be prepared. Families need to have sufficient food and water on hand for at least three days to look after themselves if they are isolated, and ensure all documentation or critical information is kept in a grab bag in case they need to evacuate.