Emergency Management Otago is part-way through a mapping exercise that would identify the coastal communities most at risk from a tsunami.
The maps, which are due to be made public by the end of the month, would use a colour-coded system to highlight areas most at risk, EMO group controller Chris Hawker said.
Red would indicate a lower-level beach and marine threat, involving a tsunami of 1m-3m, he said. Orange would highlight areas at risk from a 3m-5m wave, and yellow for a tsunami of more than 5m, he said.
The maps, which would reflect variations in topography, wave size and behaviour, would give communities more information about the risk they faced. That was particularly important if a tsunami from a close source threatened, leaving too little time for an official evacuation.
The impact of any tsunami would vary along the Otago coast, with some elevated coastal communities facing only a limited threat, while those on a river mouth, in particular, were at greater risk, he said.
''In some places, it [the wave] might go 500m inland, and in other places it might go 1km inland, depending on how big the wave is,'' he said.
The maps would be available online, but also presented to communities at risk in a series of meetings, he said.
New warning signs were also planned for at-risk areas, advising people of the tsunami threat, he said.
Meetings with community representatives would also be held to work on new community response plans, detailing what to do in a tsunami evacuation, he said.
Other measures could also be considered, including coastal warning sirens for areas most at risk, he said.
Mr Hawker was not in favour of a ''knee-jerk'' rush to install sirens right along the coast, but they could be justified in some cases, he said.
''We'll look at each community as we go and come up with what is right for them,'' he said.
His comments followed concerns late last year about the effectiveness of some aspects of the tsunami evacuation in Dunedin and surrounding coastal communities after last year's Kaikoura earthquake.
Waves of up to 3m predicted along the Otago coast failed to eventuate, but the evacuation of threatened coastal communities - like Aramoana - did not begin until hours after the first wave would have arrived.
Mr Hawker said yesterday improvements were still needed, beginning with ''good information'' for communities.
''Some of the [Civil Defence] groups around the country are further ahead with that process than we are . . . a lot of other groups, like us, are now trying to get all this information together,'' he said.
