Welsh health minister Edwina Hart has accepted that the wholesale overhaul of the NHS in Wales will not be complete until next October.
She had been aiming for the spring or early summer but delayed the process after managers said the timescale would be unworkable.
Eight trusts and 22 local health boards are being replaced with seven unified organisations, merging primary and secondary care and eliminating the internal market.
Ms Hart this week clarified the timetable for the reforms. "It is better to get this right even if it takes a little bit longer," she said.
Chairs and vice-chairs of the new organisations will be appointed early next year. Transitional directors for each new organisation are expected to be named shortly and will be senior managers, but not seen as "chief executives in waiting".
Ms Hart also said the new bodies would be set up in the style of the existing local health boards, which have around 20 members and extensive representation from local authorities. There will be further consultation on the model next month.
Welsh Conservative health spokesman Jonathan Morgan said the larger model could "deter [trust] chief executives because they feel it could simply be too cumbersome".
Managers had welcomed the restructuring, first proposed by the Welsh NHS Confederation, but said the original timetable could not be met.
NHS Wales chief executive Ann Lloyd said: "There is huge uncertainty about the change, but I believe the future is exciting."