The department can certainly release information that it has received from the commissioner, but in doing so, it must certainly not disclose the identity of a requester who has not been otherwise made public.
A department will, of course, be careful as well in not disclosing information in the commissioner's report to it that may itself contain confidential information, because in the commissioner's investigation you will have access to more confidential information, information that perhaps the government would not want to release if it was requested. And that will be taken into account by the government department in deciding what to release.