A teacher says the ministry made it hard for staff to complain about years of alleged abuse.
The Ministry of Education suspended the centre's license on November 23.
"All children in the care of the state should be safe from harm, but... all too often, the opposite was true."
It emerged Brent Ruddell gained access to all his victims by preying on vulnerable solo mothers.
Seven men face sex and drugs charges in relation to alleged abuse at Dilworth from the 1970s to 2000s.
NZ Police sent Australian Federal Police a tip-off into the man's alleged grooming of the young Kiwi girl.
It's also alleged they were mentally and physically abused.