Trains in and out of Auckland's Britomart station were stopped due to a person on the tracks in the tunnel.
The incident unfolded at a peak time for the station as commuters flooded the central city Britomart Station at rush hour.
Herald reporter Lynley Bilby was on a train heading into the city.
She said trains had been stopped from entering Britomart. An announcement over the loudspeaker said there was a person on the tracks in the tunnel, she said.
A police spokesman said police were called to Britomart about 4.40pm as a train driver had spotted a man walking in the tunnel away from the station.
All trains in and out of the station were stopped while the man, who was described as being dressed in black, was retrieved.
He was taken into custody by police. The spokesman was unsure whether the man would be charged.
Auckland Transport spokesman Mark Hannan said the incident was over by 5pm and all services were resumed.