Fletcher Building is warning its coming year's earnings will be hit by $10-$30 million because of problems with the ship transporting its cement around the North Island.
The company said the Marine Vessel Aotearoa Chief (MVAC), owned and operated by a third-party provider, has mechanical problems and is stuck at Northport at Whangārei.
The vessel carries cement from Fletcher Building's Portland plant near Whangārei to outlets around the North Island.
Fletcher Building said the vessel was being inspected and repairs being made, although it was not known how long that would take, and in the meantime it was looking at greater use of rail and road, as well as coastal barging.
"Our key priority is maintaining the supply chain and this is being actively worked through in order to minimise any potential disruption to North Island customers while the MVAC is being repaired," it said in a statement to the NZX.
It said it was also looking at getting alternative cement supplies from local or foreign producers, as well as looking for a replacement ship.
Fletcher Building said the estimated impact on 2024/25 earnings would be the higher costs incurred in ensuring supplies.