More than 600 properties in Whanganui's College Estate were left without power after a digger struck an underground cable.
Powerco said the outage occurred at around 11am on Wednesday.
The 492 properties were reconnected by 11.35am with a further 57 reconnected by 11.54pm.
Powerco said crews were currently on site and working to make it safe, carry out repairs and restore power.
The remaining 58 properties were expected to have their power restored by 3pm on Wednesday.
