Power has been restored in Toronto's financial district after thousands of white-collar workers were without power on Thursday afternoon.

Toronto Hydro says about five to six buildings were affected including First Canadian Place West, where the TSX is located, the RBC Centre, and GO Transit at 335 Front St.

These building are located on Wellington, Front, Richmond and King Streets.

Toronto Hydro say they are unsure what caused a "feeder trip" which led to the outage. A feeder is the primary wire that carries power.

Most of these buildings have backup generator power.

There were no reports of people stuck inside the buildings or elevators. Toronto Hydro estimates there are about 10,000 and 20,000 people in each of the buildings.