The Ministry of Civil Defence and Emergency Management (MCDEM) said surges of up to 30cm were expected along the Otago coast from Oamaru to the Catlins from about 2am tomorrow.
A tsunami warning has been issued for the entire east coast of New Zealand and the Chatham Islands.
MCDEM is assessing the tsunami threat to New Zealand, and the Otago Civil Defence and Emergency Management Group has been monitoring the situation locally.
Otago CDEM Group controller Jeff Donaldson said southern marine and beach areas could expect unusually strong currents and unpredictable water flows near the shore.
"The severity of currents and changing water flows will vary within a particular coastal area and over the period this warning is in effect," Mr Donaldson said.
"Current assessments indicate that coastal inundation (flooding of land areas near the shore) is not expected but this assessment may change."
Mr Donaldson said the first activity to hit NZ may not be the most significant.
Tsunami activity would continue for several hours and the threat must be regarded as real until the warning issued by MCDEM is cancelled.
Otago people are advised to take the following precautions:
1 Stay out of the water (sea, rivers, and estuaries) and not go boating
2. Stay off beaches and shore areas
3. Do not go sightseeing
4. Share this information with family, neighbours and friends
5. Listen to the radio and/or TV for updates
6. Follow any instructions from local civil defence authorities.
Everyone in Otago coastal areas, including whitebaiters and fishermen should be sure to follow these precautionary measures.
