Bio-pharmaceutical company BioMarin is to invest almost €37m at its plant at Shanbally in Co Cork.
The company says the investment is expected to lead to the creation of more than 50 jobs, bringing employment at the plant to over 400.
BioMarin manufactures drugs and therapies to treat rare genetic diseases which mostly affect children.
The company has seven approved products which are the only drugs available for the diseases they treat.
It established a plant at Shanbally near Ringaskiddy seven years ago. The plant has been expanding almost continuously since it opened.
BioMarin's Executive Vice-President Robert Baffi announced the expansion in a meeting with staff at the plant this morning.
The investment will allow the company to finish and pack drugs ready for market at the plant.
Mr Baffi said the expansion would make the Shanbally plant a fully integrated manufacturing facility, from bulk ingredients to finished drug products.
Tánaiste Simon Coveney said BioMarin had thrived since it located in Co Cork in 2011.