Located on the Burrup Peninsula north of Karratha, the Ceres plant owned by Perdaman Chemicals and Fertilisers will be able to produce some two million metric tons of urea a year.

Urea is the most commonly traded nitrogenous fertiliser. The Ceres plant will make it by turning natural gas into ammonia and then into urea.

An outline agreement to build the plant was first announced in May 2022.

In February this year Webuild bought Clough’s assets, including its offices, 1,100 employees, and a €4bn project backlog.

The plant will be the biggest in Australia and one of the biggest in the world.

“Thanks to this contract, Webuild enters a new and promising market segment – urea production – at a time when global demand is growing,” said Webuild chief executive Pietro Salini.

He said the contract win confirmed the strategic value of the Clough acquisition.

Webuild said building the Ceres plant would create 2,000 jobs.

Australia is the second biggest market for Webuild after Italy.