Hundreds of properties have been left without power in the Lisburn, Royal Hillsborough, Dromore, Donacloney and Moira areas, NIE Networks has said.
The network operator has blamed "faulty equipment" for the outage and said repairs will start "asap".
"A repair team has been assigned and will be on its way as soon as possible," NIE Networks has said.
There has been widespread travel disruption - and some other power outages - across Northern Ireland due to the heavy rain and strong winds across Northern Ireland.
A yellow Met Office alert remains in place.
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