Janssen will build a new 19,100m
The project, which is scheduled to take around two years, will create 200 jobs when completed.
The Ringaskiddy site was opened in 2005 as a hub for the production of biopharmaceuticals for treatments for immune diseases and cancer. According to Janssen, three commercial products and various clinical candidates are made at the plant.
The firm did not respond to a request for more information.