Power was cut to more than 700 homes in and around Waikouaiti, some for several hours, yesterday afternoon.
Supply to 743 mainly TrustPower customers was lost at 1.55pm.
Workers from PowerNet, which owns the lines, restored the supply to the majority of homes about 2.20pm, PowerNet system control manager Kana Shanmuganatahn, of Invercargill, said.
Most of the remaining 280 homes had power restored about 4pm, although a few homes may have taken longer to reconnect, he said.
A recorded message on the TrustPower electricity faults phone system said the outage was caused by a car crash, but Mr Shanmuganatahn said that was incorrect.
An unknown fault had caused a circuit to trip, cutting supplies, but linesmen sent to check the lines found nothing wrong with them, he said.
