Benmore Power Station's undergoing four years of seismic upgrades to ensure it can keep generating, if the Alpine Fault ruptures.
The work will focus on strengthening the concrete penstocks - which carry water from the dam to its turbines.
Generation General Manager Tania Palmer says the upgrades will help the station get back online much faster after a quake.
She says it's a proactive investment which will reduce future disruption - adding there's no safety risk today.
