Canterbury Civil Defence controller Neville Reilly says flooding is still the biggest threat to the region despite a predicted 65 percent chance of the Alpine Fault rupturing in the next 50 years.
The regional Civil Defence Emergency Management Group, made up of mayors from the regions' councils, is finalising its plan for how to manage the areas' hazards.
Mr Reilly said the threat from the Alpine Fault had long been known but there was now more research into its likely impact.
He said if the Alpine Fault went it wouldn't be as damaging to Christchurch as the recent more localised earthquakes.
Mr Reilly said the Mackenzie District was the area most at risk from the Alpine Fault rupturing.