An independent review into the rollout of Wellington's new bus network has found several elements of the programme were delivered late or insufficiently.
The review was jointly commissioned by Greater Wellington Regional Council and NZTA.
It followed a public outcry over the troubled system.
One frustrated commuter referred to it as a "lasagne of failure" while the term "ghost bus" became somewhat of a grim joke in the capital.
The independent review said the nature of the rollout created a substantial challenge.
It acknowledged customers experienced poor reliability and punctuality post-implementation.
In Wellington city, customer complaints peaked at 11 times the normal levels.
But the regional council did have robust governance structures and processes in place and there has been ongoing and sustained improvements in the services being delivered, the report said.
The late or insufficient delivery of key milestones was due to inadequate phasing of the roll out, lack of testing, and understanding of operator readiness.
These included the bus hubs, fleet, accurate RTI information and adequately trained drivers from original planned timelines.
The report has found the collective capability of the public transport team and dedicated programme team was insufficient for the transformational nature of the changes required.
Council chair Chris Laidlaw acknowledged they had "fallen short" in some areas causing regrettable disruption for some bus customers.
"Since July we have been listening and working closely with community groups and operators to increase services, adjust timetables, ensure the right size bus turns up, provide better data and information to the public, and put things right."
The review looked at the implementation of the new network, and not the inherent design and philosophy behind it, or the limitations of the Public Transport Operating Model provision.
These will be dealt with in a later stage of the review.