Power has been restored in Toronto's Forest Hill neighbourhood, where more than 700 residents had been without electricity since Monday night.

The outage began shortly before 9 p.m. Hydro spokesperson Tori Gass said a fault in an underground cable is to blame.

"What's tricky with this is it's not always easy to locate something when it's underground," Gass said. "They've narrowed it down to a certain area, but the exact fault in the cable is still proving a little elusive."

The affected area is between Briar Hill Avenue, Eglinton Avenue West, Bathurst Street and Latimer Avenue. 

Toronto Hydro had originally estimated the power could be back on by mid- to late-morning. Shortly before 9 a.m. Tuesday, the utility said the outage would likely stretch into the afternoon.

Power was eventually restored around 2 p.m. Tuesday.

Gass said crews are bringing in specialized testing equipment to pinpoint the issue. They are hoping to restore power by mid- to late-morning.

The outage comes as Toronto remains under a heat warning. Temperatures are expected to climb to the low 30s, with humidex values approaching 40 C.

"It can be uncomfortable for our customers — we feel for them right now," Gass said. "While we can't say exactly what the cause of this is, we have been seeing some scattered outages in the last two nights throughout the city, and it wouldn't be farfetched to guess that this is related to the heat."