Earlier, the agency said on Twitter: "Train services on the Eastern and Southern lines are currently operating at a reduced frequency - approx every 20 minutes due to an overhead line issue near Westfield. There are also delays to services into Britomart due to a track fault."
An Auckland Transport spokesman told the Herald at 9.33am that "recovery is in process and trains are expected to resume normal schedule at approximately 10.30am."
"The Eastern and Southern line services were delayed this morning due to an overhead powerline issue near Westfield. The fault was fixed by KiwiRail at 8.10am," he said.
"Trains have been operating out of Britomart all morning. During this time, services on these lines were halted between Otahuhu and Manukau [Eastern Line] along with Penrose and Papakura [Southern Line].
"Trains have resumed running on the full line, at a 20 minute frequency.
"Western and Onehunga lines are experiencing delays due to congestion near Newmarket and Britomart [lack of track space].
"Recovery is currently in process and trains are expected to resume normal schedule at approximately 10.30am."