The significant outage affected the inner city, as well as Bond and Mersey Sts.
PowerNet said the outage happened at 10.25am and was caused by an underground cable fault. Power was restored by about 11.30am.
Invercargill City Library had to improvise during the cut.
Customer experience manager Cynthia Smith said a school-holiday book reading session needed to make use of the natural light.
''We moved the people from the room to a space near the window. At least they had something to be entertained.''
Quest Apartments owner Marc Williams said the situation was difficult, as all his systems were off and customers were not able to check in.
''We hope customers don't complain on the review websites, but it is not our fault.''
Maher Outlet manager Sam McPherson waited outside so any customers wanting to browse through the store knew it was still open, she said.
Lunch time was the busiest period of the day for business.
''I can open the store but I can't take eftpos transactions. Customers need to get cash out.''
Four sets of traffic lights on Dee St were also without power for an hour.
-By Abbey Palmer
