He blames in part the "overriding concern" of protecting the institution for abuse at the facility and claims medical recommendations were frequently not accepted and delayed.
He claimed the department told him medical recommendations to evacuate asylum seekers to Australia for treatment would "undermine" the offshore detention policy and allow access to lawyers.
Further, following the fatal riots at the facility in 2013, department officials said mainland evacuations for treatment would not be approved "anytime soon" even if the asylum seeker had no involvement in the violence, Young told the committee.
"That was quite appalling when we knew we had a number of people on waiting lists," he said, adding he was told all asylum seekers were responsible for the riots because they were all there.
Young is the former director of mental health services for International Health and Mental Services, a private contractor employed by the immigration department.
- AAP