Downtown Auckland has ground to a halt with power outages causing traffic jams and public transport delays in the CBD.
Power was initially out at Britomart, Newmarket and Parnell but was soon restored just after 1.30pm.
However, the impact is set to be felt for hours with train services delayed until 3pm.
"Power at the Britomart Train station has now been restored. Trains will now be arriving and departing from Britomart," Auckland Transport announced.
"Please expect delays and cancellations until services return to normal. Normal services will resume at 3.00pm."
Many roads in Auckland's CBD are jammed, with Queen St, Wellesley St West, Albert St, Mayoral Dr, Cook St, Customs St East, Karangahape Rd and Beach Rd experiencing heavy traffic congestion.
Vector said at 1.45pm that power had been restored to the CBD, though parts of Parnell were still without power.
Traffic lights were previously out on the corner of Wyndham and Queen St.
Mayor Phil Goff said: "The outage is affecting traffic signals and public transport, so please take extra care on the roads."
Earlier, Vector confirmed the outage had affected Quay St, parts of Auckland's CBD and parts of Parnell.
"Vector's electricity operations centre is remotely redirecting power flows to as many affected customers as possible, and our crews are currently working on the fault," the company said.
"Customers in these areas should prepare to be without power for some time while we respond to the outage. The objective of our crews is to do this as quickly as possible while ensuring the safety of our crews and the public."