A newly discovered active fault line along Wellington's harbour could result in a large quake for the city, scientists say.
The Aotea Fault so far measured 2km long and ran from Oriental Parade to Westpac Stadium, said National Institute of Water and Atmospheric research (Niwa) marine geologist Philip Barnes.
However, data shows the fault could be up to 30km in length, running onshore across the city to the Cook Strait on the southern shoreline, he said.
"It needs more research."
The fault could produce an earthquake measuring up to 7.1 in magnitude, which could result in the ground being displaced by 2m.
It had already been responsible for two large earthquakes in the past 10,000 years, Dr Barnes said.
The first, 8400 years ago, plus or minus 1300 years, offset the ground by 4m.
The second, 6200 years ago, plus or minus 900 years, offset the earth by 2m, he said.