Essential Energy says a possum was the cause of the power outage at Broulee on Monday night through to Tuesday evening (April 5-6).
Specialist crews were called to repair significant damage to the electricity network which affected 1742 homes and businesses.
South Eastern operations manager Darren Basterfield said Moruya crews were sent to determine the cause of the outage.
"For the safety of the public and property, the electricity network switched itself off at 10.02pm, after detecting a problem," he said.
"Crews patrolled the electricity network and identified a possum had contacted high voltage equipment on the electricity network, resulting in the unplanned outage."
Once safe to do so, power was restored to 1076 Essential Energy customers at 11.57pm and a further 401 customers at 12.42am on Tuesday morning.
Mr Basterfield said the network suffered significant damage which required extensive repairs to be completed before power was restored to the remaining 265 customers at 6.42pm on Tuesday evening.
"The complex nature of the damage - which occurred where an underground cable meets with overhead power lines - meant it was not possible to reroute power to customers around the fault and specialist crews were needed to be brought in to complete repairs," Mr Basterfield said.
"Essential Energy sincerely apologises for any inconvenience caused and thanks customers for their understanding."
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