Civil Defence has released new maps of the Otago coast that grade which individual properties would be evacuated in a tsunami alert.
The new searchable internet-based maps on the Emergency Management Otago website mark out three coloured zones in red, orange and yellow depending on the height of tsunami waves hitting the coast.
The maps follow a new national standard for tsunami risk.
The red zone - "beach and marine threat" - covers all of Otago's beaches, estuaries and harbours.
Hundreds of properties have been coded orange as they would be hit by a 1m wave, and thousands of properties are coded yellow for a wave greater than 3m.
Emergency Management Otago's regional manager, Chris Hawker, believed the maps would make emergency evacuations much faster.
"If in an emergency people are told the orange zone is being evacuated and they already know they are in that zone, it will make for much faster and better decision-making," Mr Hawker said.
A new national cellphone broadcast system being rolled out next month will add to the tools to get tsunami alerts out quickly, he said.
Together with the maps, the system is a big improvement on what the country had during last year's Kaikōura earthquake, Mr Hawker said.
"Kaikōura was definitely a wake up call," he said.
"The indecision that followed the tsunami risk to Kaikōura is something that none of us wants to see again.
"All of the civil defence groups have been working with the ministry to talk about how we prevent that kind of situation occurring again."