A series of major government projects across Northern Ireland are running years late and millions over budget, a report warns today.
Too many are not meeting their cost and timescale targets, auditors said.
In one case, the Regional Children's Hospital has been delayed by five years and is close to 60% over initial cost estimates.
A new maternity hospital is also running six years late and 30% over budget.
They are among seven flagship infrastructure projects identified as high-priority by the Executive in 2015. None will meet their original time and cost estimates.
Other examples include the A5 Western Transport Corridor - our biggest ever roads project - and the redevelopment of Casement Park. A critical care centre, originally intended to open in 2012, is also eight years late and 60% over budget.
A report published today by the NI Audit Office criticised "cumbersome governance and delivery structures" in the public sector and said a change of approach is needed.
Auditor General Kieran Donnelly said: "Major capital projects are complex and delivery problems are not unique to Northern Ireland.
"That said, it is disappointing that, while some projects are delivered on time and within budget, many suffer significant cost overruns and time delays.
"Even flagship projects identified as the Northern Ireland Executive's highest priority, and with funding secured over a longer period, have not met their original delivery targets.
"Existing, cumbersome governance and delivery structures within the Northern Ireland public sector can be a barrier to achieving value for money.
"I believe there is merit in considering alternative models, sufficiently resourced with specialist staff, to help improve future delivery."
Over the last eight years, almost £10.6bn was spent on public infrastructure.
In that period, departments managed 54 major capital projects worth £5.5bn. Most of these were managed by the Department for Infrastructure (DfI) and the Department of Health (DoH).
In 2015, the Executive identified several high-priority flagship infrastructure projects. In each case, auditors identified time delays and/or cost overruns.
Three projects encountered significant problems:
Auditors also identified problems with:
Today's report states: "While accepting that project delivery problems are not unique to Northern Ireland, it is disappointing that, in the 11 high profile projects considered in this report, costs and timescales envisaged at the outset of projects, were not achieved."
Auditors said the "public sector faces significant challenges delivering against its major capital projects portfolio".
"From our high level overview of a number of projects and our focus group, we identified that challenges typically include funding difficulty or uncertainty, challenges through the courts, delays with planning or a lack of appetite and capacity within the local construction industry to take on public sector work."
The Audit Office plans two more studies - one of the planning system at central and local government level and the second on lessons arising from judicial reviews.
The DfI Belfast Rapid Transit project was the only project examined that was delivered within the estimated costs outlined in the initial business case, although the final cost slightly exceeded the cost outlined.
DfI expects two of the three elements of its flagship A6 project to be delivered for close to, or less than, the estimated full business case cost and within one year of the estimated timescale. The third element is on hold.
Two projects of the Regional Stadia Programme were delivered within budget and broadly within time estimates.
In response the Department of Finance said: "A number of capital schemes were subject to legal and planning challenges which directly impacted on timescales and resulted in delays in some cases. The relevant departments who are responsible for the individual projects engaged with DoF at the outset to get the necessary business case approval. In addition where there were significant changes to the scope or cost of the projects, departments were required to seek further DoF approval in those cases."