Work on the next stage of the redevelopment of the Ulster Hospital in Dundonald is to begin later.
The investment of £232m will provide a new ward block and an acute services block.
The new ward block will replace the existing main wards which were built in 1962.
It is due to be finished in early 2017 and will include 12 inpatient generic wards, day surgery, pharmacy and support services.
The second phase, the new Acute Services Block, will provide 170 beds and is expected to open to patients in early 2018.
The Health Minister, Edwin Poots, who will cut the first sod, said it marked the beginning of the next vital phase of redevelopment.
“A number of new facilities, such as the Renal Unit and Critical Care Unit, have already been constructed and are operational on the site,” he said.
“These modern facilities will be constructed using the latest innovations in design and technology and will be well-equipped to provide secure, safe, high quality services to patients.”