A source close to the project said that the programme was likely to slip. The source said: "It was initially supposed to be finished in May. There is a project completion date of September but I could see that being pushed back to Christmas."
Gleeson started work on the civil and structural steelwork element of the project in a joint venture with Danish contractor Monberg & Thorsen in 2000.
A source said one problem was that Gleeson was not in control of the design. He said: "The design is not coming through to Gleeson, which is holding things up."
The company pointed to the emergence of "fundamental disagreements" over the interpretation of the project's contract conditions in a statement last week.
The statement said: "The board is convinced that the group is not being treated reasonably or fairly and proposes to pursue its claims for additional payment with extreme vigour." Gleeson said that its divisions were generally performing well despite this setback. The firm will post its half-year results next week.