There was disruption to many Aucklanders' morning commute today as trains across the city were cancelled.
Auckland Transport (AT) said all southern and eastern line services had been cancelled between Ōtāhuhu and Britomart.
"All Western & Onehunga Line services have also been cancelled until further notice, due to a Kiwirail track infrastructure problem," AT said in a statement posted on social media.
Some train services are now back up and running, however, AT warns commuters to expect further delays and cancellations to services across the network.
In an update at 9:30am, AT said train services are now running on the southern, western and eastern Lines after the KiwiRail power outage was resolved.
It said services are running to 20 min frequencies for the remainder of the morning peak instead of the usual 10-minute frequency.
"We do not yet have a timeframe for services resuming on the Onehunga line– we will keep our customers updated on progress restoring services through our usual communication channels," AT said in a statement.
A rail replacement bus on the Onehunga line will be running and customers can also the 30, which runs frequently between Onehunga and the CBD.
AT said it is meeting with senior KiwiRail executives on Friday afternoon to discuss this issue.
KiwiRail said in a statement at 8:15am electrical arcing was discovered between overhead powerlines in Auckland's Newmarket area.
"For safety reasons, power to the overhead lines had to be turned off between Penrose, Swanson and Britomart - so the electric commuter trains cannot operate," KiwiRail chief operations officer Siva Sivapakkiam said.
"Our technicians have been on site this morning and have assessed and repaired a fault. We are aiming for the power to be switched back on shortly, so that train services can resume.
"KiwiRail has been working to fix the fault as quickly as possible, and have been keeping Auckland Transport and Auckland One Rail informed."
Trains are still running between Papakura and Otahuhu on a reduced timetable.
Appearing on AM earlier in the morning, Transport Minister Michael Wood said the cancellations were frustrating for commuters.
"Obviously really frustrating and difficult for commuters who have turned up but hopefully that will be resolved soon. There are other public transport services that will be made available," Wood told AM co-host Ryan Bridge.
A commuter told AM the New Lynn Station is "packed" and buses are getting "pretty full".
A spokesperson from AT initially said the southern line is estimated to be restored at 7:30am, however, that was pushed back.
AT group manager metro services Darek Koper confirmed in a statement at around 7:30am, a "significant fault" with KiwiRail's overhead power lines at Grafton was behind the cancellations.
"We are advised that KiwiRail will fix this issue in the next hour or two but unfortunately there will still be flow-on cancellations and delays all morning as a result of the enormous disruption to our services so far," Koper said.
"Tens of thousands of Aucklanders rely on our rail network every day to get to school, work and to access essential services. It's hugely disappointing and frustrating that we are not able to operate our services as usual this morning."
Koper said due to the short notice of the outage, AT has only been able to arrange a small number of rail replacement buses.
At this stage, there is only one rail replacement bus for each of these lines.
Services on the southern and eastern lines are running as far as Ōtahuhu, with a limited number of rail replacement buses operating between Ōtahuhu and Britomart.
Because of this, AT is encouraging train customers to consider using one of the scheduled bus services instead.
"Once power has been restored today and our trains are up and running we will be seeking more detailed answers from KiwiRail about the cause of this morning's outage and what steps they will take to prevent such issues happening again in future," Koper said.
The National Party's transport spokesperson Simeon Brown has hit out at the cancellations, asking for answers from KiwiRail on why it has "effectively shut down" the Auckland rail network.
"This will cause chaos for Auckland commuters and follows similar major disruption caused for many thousands of rail passengers in Wellington this week, due to the capital's rail network having not been checked by Kiwirail’s one and only track evaluation car," Brown said in a statement.
Kiwirail has noted Friday morning's fault is unrelated to issues with the Track Evaluation Car which caused disruption in Wellington earlier this week.
Brown claimed Labour has allocated more than $8 billion dollars to Kiwirail since becoming Government, but said passengers are not seeing the benefits they should expect from that investment.
"A resilient and reliable public transport network is critical to getting people to use public transport," he said.
"This failure does nothing to help achieve that shift."