Sri Lanka has been hit by nationwide cuts, including hospitals having to rely on generators to supply power.
The power outage that started around 11:30 local time (06:00 GMT) has not been completely fixed.
The Ceylon Electric Power Commission (CEB) said the cuts were caused by emergency sub-sites and it was working to restore supply.
Energy Minister Kumara Jayakody blamed a monkey for the reported power outage, saying the animal “contacts with our grid transformer, causing the system to be imbalanced.”
“Engineers are working hard to resume services as soon as possible,” the minister said.
“We are doing everything we can to restore island-wide power failures as soon as possible,” CEB said.
There are 22 million hospitals and businesses on the island who have been using generators or inverters.
Sri Lanka Has experienced extensive power outages During the 2022 economic crisis.