An emergency alert was sent to mobile phones in the area at about 5.45pm telling people to close all doors and windows.
"There is a gas leak at the intersection of Customs Street East and Gore Street in the Auckland CBD. Close all doors and windows. If you have any concerns, please call Fire and Emergency. Alternatively, EVACUATE the immediate area and follow instructions from local authorities. Please stay away from the area to allow emergency vehicle access," the emergency alert read.
Part of Customs St has been cordoned off from Albert St as emergency services respond. Beach Rd is also closed from to Anzac Ave.
A Herald reporter at the scene said the "smell of gas is very strong on the corner of Customs and Commerce".
A Vector gas emergency response van has just entered the cordon.
Fenz said crews were called to a gas leak at 4.48pm this afternoon.
"There are currently four fire crews and support crews with gas detection equipment in attendance. The leak is coming from a manhole."
Deputy National Commander Brendan Nally said: "We ask anyone near the intersection of Customs Street East and Gore Street to keep their doors and windows closed.
"We also urge members of the public to avoid the area to allow our crews to continue working on site and to ensure emergency vehicles have access to the area."
Auckland Transport has detoured buses that terminate at Britomart.
At least 17 buses are backed up on Gore, Fort and Commerce Streets.
"Wake me if we start moving," one bus driver, forced to wait behind the cordon told the Herald.
A spokesman for police said there was "a suspected gas leak on the corner of Queen and Customs [Sts]".
"[Fire and Emergency NZ (Fenz)] is the lead agency. Police are providing traffic management," he said.
Commuters have been told to expect delays and follow the directions of emergency service or transport staff.
The Herald has approached Fenz for comment.
