The Ceylon Electricity Board says it will take at least up to another three hours to completely restore the power supply.
An island-wide power outage was reported earlier today.
The CEB said the power supply has already been restored to several areas in Colombo.
The Ministry of Power said the island-wide power outage was reported at around 11.45am due to a breakdown in the transmission lines.
The Ministry said necessary steps have been taken to restore the power supply promptly.
Power outages were also reported in the past few days in several areas as well.
Meanwhile, traffic congestion has been reported in some areas with traffic lights not functioning in main roads while train delays are also expected until the power supply is restored.
The water supply has also been disrupted to several areas in Colombo and suburbs owing to power cuts.
The National Water Supply and Drainage Board attributed the water cut to power disruptions reported across the country.