More fault lines have been discovered under Hamilton in New Zealand, which may increase insurance premiums.

University of Waikato field researchers found 25 potential fault zones between Cambridge, which is about 23km southeast of Hamilton, and Taupiri, about 25km to the north. Four of the faults are “potentially active”.

Researcher Willem de Lange says the maximum earthquake magnitude for Hamilton remains the same, but an event is more likely to be “localised”, with more damage to infrastructure.

Excavations for the Waikato Expressway road-building project have also uncovered several fault zones.