Pump trucks are currently on site as a flooded carpark and substation that caused a massive power outage in Melbourne’s CBD.

Citipower said they would have crews working through the night to remove “thousands of litres of water” and begin damage assessments and repairs.

“Our teams are working through the night to continue to restore power to more customers and repair damage to equipment as quickly and safely as possible,” they wrote in a statement.

“We appreciate it’s difficult to be without power for any length of time and we thank all of our customers who may be affected by this outage for their patience.”

As of 7.30pm, 1149 customers still remained without power.

The Epworth Freemasons hospital in East Melbourne lost power when the substation flooded.

A hospital spokeswoman said the hospital was running on emergency lighting until full power was restored at 8.30pm.

VicTraffic said the “large power failure” about 5.30pm on Monday resulted in 40 sets of traffic lights out across the Melbourne CBD, East Melbourne and South Yarra.

“When traffic lights aren’t working, you must follow the same rules at an intersection which has a stop or give way sign or line,” VicTraffic wrote on social media.

Citipower and Powercor said in a statement that a burst water main had flooded a public car park at 32-60 Little Collins Street.

A video posted by Jacqui Felgate shows a car park on Little Bourke St submerged, with multiple cars left behind in the water.

The water entered a zone substation located in the basement of the facility which resulted in the power from the site being turned off for safety reasons.

About 10,000 customers in the southeastern suburbs were initially cut off.

4000 customers have since had their power restored.

Citipower said about 5,700 customers remain without power.

“Our crews are on site and working to remove the water,” Citipower said in a statement.

This will allow safe access to the zone substation so any damage can be assessed.”

Customers are reminded to wait for updates via SMS or by visiting the Citipower website.