UPDATE - 4.15pm
More than 8000 electricity customers have had their power restored after an outage lasting about 30 minutes on Wednesday afternoon.
Wholesale distributor Essential Energy restored service to areas around Wagga Base Hospital and east of the city at about 3pm.
The cause was identified as a "foreign object" contacting power lines at Turvey Park in the vicinity of Coleman and Mitchelmore streets.
Essential Energy operations manager for Riverina Slopes, Shawn Eade said "crews responded after protection equipment operated isolating electricity supply to customers at approximately 2.35pm."
"Crews were able to reroute the electricity supply around the fault area and progressively restore supply to all customers by 3.00pm" Mr Eade said.
Essential Energy has urged residents to be cautious around fallen power lines and other electrical hazards.
"Residents are reminded to report fallen powerlines, network damage, fires or trees contacting powerlines to Essential Energy on 13 20 80 or call Triple-0 if the situation is life threatening," Mr Eade said.
Earlier - 3.05pm
Sturt Highway traffic lights and more than 1400 Wagga homes and businesses were left without power on Wednesday afternoon.
Police were called to direct traffic on Edward Street between Best Street and Docker Street.
Wagga Base Hospital and Calvary Base Hospital were affected by the outage.
A Murrumbidgee Local Health District spokesperson said Wagga Base Hospital was was affected by the power outage for about 10 minutes.
"The back-up generator kicked in straight away and there was no impact to patient care," the spokesperson said.
Wholesale electricity distributor Essential Energy reported two areas of outages in Wagga just after 2.30pm, with one area near Wagga Base Hospital between Dobney Avenue and Coleman Street.
A larger outage area, comprising more than 1000 customers, was reported between Riverview Drive in Moorong and Pearson Street in Wagga.
Essential Energy has not listed an estimated time for when the "unplanned interruption" will end.
The NSW Government's Livetraffic service has warned of multiple traffic lights being affected due to a "power failure".