A vast area of Chile, including the capital city of Santiago, was plunged into darkness Sunday by a massive blackout, the National Emergency Office said.

The area affected covered a 1243 miles stretch affecting about 80 per cent of Chile's population of 17 million people, officials told AFP.

The blackout was caused by problems with a 500KW transformer - a device that transfers electrical energy from one circuit to another - Chile's Interior Minister Rodrigo Hinzpeter said, according to Reuters.

The electricity problems were not believed to be directly related to the massive earthquake that struck on February 27, the minister said, but there would be an investigation to confirm this.

Power was slowly being restored in parts of Santiago and was expected to be running normally by midnight.

There were no inital reports of public disorder, Reuters reported.