Internal audit department should have staff with diverse backgrounds. Of most importance is certainly finance and IT.
I'm an internal auditor in a group of companies. The subsidiary companies span different industries in the manufacturing sector. The portfolio From food producing companies, textile, steel, pharmaceutical packaging and printing.
To audit these companies the department require people of diverse skills. For instance our department team have members with different backgrounds i.e legal, engineering, commerce, economics and agriculture.
This helps us to combine knowledge and execute audit assignments effectively.