One of the main commuter railway lines in Auckland remains closed on Monday because of difficulties with new signalling at the Newmarket Junction.
The delay follows three weeks of extensive work on the line.
Replacement bus services will continue and some train services will be added to the Western line.
Project director Murray Hood says it's better to retain the timetable commuters have been using for the past three weeks than to offer a service that could be disrupted.
Mr Hood says it's disappointing that resumption of full service has been delayed, but says commuters prefer certainty.