The Justice Precinct and the Convention Centre accounted for about $193 million of losses at the company's Building + Interiors unit in 2017.

Fletcher Building also expects they will also drag down the unit this financial year, hitting B+I by about $100m in 2018.

That accounts for about 80 per cent of the $125m project losses in 2018.

"I want to offer my personal apology to our shareholders," chair Ralph Norris said. "Mistakes have been made and responsibility ultimately rests with the board. As we stated at our full year results briefings, we fully accept this responsibility."

The company said today it had not named the projects previously because of "strict confidentiality clauses in our contracts".

"We take our obligations to our clients very seriously," the company said.

"Unilaterally deciding to ignore our contractual requirements would simply put at risk our client relationships and our ability to win work in the future, which is not in the best interests of our shareholders," it said.

"However, in the face of these extenuating circumstances and shareholder demand, we have been able to gain agreement from our clients to make an exception in this instance.

The convention centre was one of the projects reviewed recently by KPMG, the others being Commercial Bay in downtown Auckland and the Puhoi to Warkworth and Hamilton City Edge Expressway projects.

"In three out of the four projects reviewed, KPMG's forecast outcome is broadly in line with management's expectations - risks and opportunities exist on each project, however final margins in all three cases are expected to be positive. The key issues identified relate to the [conference centre]. which has already been identified as a major contributor to the company's losses in [2017]," Fletcher said today.