Auckland Transport has apologised for recent disruptions on the rail network including track and signal failures (operated by KiwiRail), mechanical breakdowns with the old diesel trains and staffing issues.
For the past two days Auckland train commuters have faced delays because of a "crew matter".
An announcement at stations said this was causing a number of train service delays and cancellations.
General Manager AT Metro Mark Lambert says a new timetable has also caused difficulties.
"The new timetable from December 2014 introduced a 20% plus increase in services across the constrained Auckland rail network making it difficult to recover when there is an issue. We are working with the rail operator Transdev to speed-up the recovery time when unfortunately inevitable failures occur."