An ageing underground cable has been blamed for a power outage that left 994 Tauranga customers without electricity on Monday morning.

Powerco said the outage was caused by a cable fault, which can occur as electricity infrastructure ages.

"The fault was in a 300m run of cable at the intersection of Cameron Rd and 2nd Ave," Powerco said in a statement.

"Our contractors are currently working to locate the exact location of the cable failure. Once this has been identified, an appropriate repair or replacement can be carried out."

The outage affected properties in central Tauranga.

Power went out at 8.09am and affected customers in and around Tauranga’s CBD.

Traffic lights were also reported to be affected by the outage, social media posts said.

Power was restored to most of the affected customers within about one-and-a-half hours

In today's statement, Powerco said all customers affected by the outage have now had their power restored.