A powerful aftershock shook New Zealand's South Island Monday, just hours after being hit by a powerful 7.8-magnitude earthquake.
"It looks as though it's the infrastructure that's the biggest problem," said Civil Defense Minister Gerry Brownlee after flying over the affected area with Prime Minister John Key.
A slip dam caused by earthquakes had blocked the Clarence River until it broke, sending a wall of water downstream, forcing people to move to higher ground.
Key said he expects the damage bill will be a least "a couple of billion dollars" and will take "months of work."
John Kirby, a spokesman for U.S. Secretary of State John Kerry said the top American diplomat offered New Zealand Foreign Minister Murray McCully "whatever U.S. assistance might be required."
New Zealand officials confirm two people have died after a powerful 7.8 earthquake hit 90 kilometers from Christchurch, the biggest city on New Zealand's South Island.
The quake caused some damage to buildings more than 200 kilometers away in the capital, Wellington.
Reports say thousands of residents in the coastal area of New Zealand fled their homes for higher ground after tsunami warning sirens were activated in South Island coastal towns.
Police and emergency workers went door-to-door to evacuate residents living in seaside properties.
Ministry of Civil Defense said waves up to five meters could possibly hit towns.
"The first waves have arrived, but we know that it is too early to say what the impact has been," Sarah Stuart-Black, national controller at the Ministry of Civil Defense, said.
"Our concern is what is coming. Future waves... may be bigger that what has come before," she said.
Some early waves were up to two meters and officials described the tsunami as an "event of life-threatening or national significance."
St. John Incident Controller Dion Rosario said emergency personnel started to "get reports of injuries from the earthquake area, including Culverden area and Kaikoura."
A 6.3 quake in Christchurch in 2011 killed 185 people and caused widespread damage.
The main tremor was followed by a series of strong aftershocks.
A 6.3 quake in Christchurch in 2011 killed 185 people and caused widespread damage.
