Auckland Transport alerted social media followers around 6.30pm about the "serious incident on or near the rail corridor" which was causing disruptions.
"Please expect some disruption to scheduled services across the Western line due to an emergency services incident at Britomart," the statement reads.
"A serious incident on or near the rail corridor with emergency services in attendance.
"Emergency services site clearance is required before services can resume."
A police spokesperson and Fire and Emergency New Zealand spokesman both confirmed with the Herald they had no appliances in attendance.
AT spokesman Mark Hannan did not know any details about the incident.