The Department for Infrastructure has spent £110 million on the A5 road project without a spade going into the ground.
Plans to upgrade the 58-mile dual carriageway between Derry and Aughnacloy was first unveiled in 2007.
But since then it has been plagued by legal challenges in the courts and funding issues.
MLAs on Stormont’s Infrastructure Committee have been told it has already cost £110m even though construction work yet to begin.
Three years ago the figure stood at just over £80m.
DfI officials also said a long-awaited decision on the A5 could be made “towards the end of the summer”.
“There are still some outstanding elements but our intention is to put a series of papers to the executive over the summer with the view to a decision being taken later in the summer,” Colin Hutchinson, the DFI’s project director, told the committee.
Since 2006, 56 people have died on the A5, according to the department.
Families who have lost loved ones on the road have called for Infrastructure Minister John O’Dowd to prioritise the upgrade.
Officials said the proposed upgrade would save lives.
A public inquiry in 2023 heard arguments for and against the scheme, and its final report contained 30 recommendations.
The committee was also told Infrastructure Minister John O’Dowd had not met representatives from the Alternative A5 Alliance, which has launched legal challenges against the scheme.
But it was confirmed DFI officials had been in contact with the lobby group.
The committee was also told the total cost of building the A5 currently stood at £1.7bn, with €600m (£508m) coming from the Irish government.
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