Roach announced his decision not to seek reappointment at today's annual general meeting of the organisation.
Deputy chairman Neville Stevens was elected to fill Roach's post, a statement from NICTA said.
Roach played a key role in delivering credibility to NICTA -- which is managing more than AU$500 million in public funds -- with his four decades of experience in the industry, including seven as chairman of Fujitsu Australia. The organisation now has 16 research programs underway, more than 10 individual projects and about 350 staff and students.
Other board members to depart include chief executive and president Dr Mel Slater, Professor Tony Blake, Professor Graham Goodwin and Alice McCleary. Their replacements are Jennifer Clark, Professor Michael Brooks, Kelly Jones and Dr Michael Sargent.