If access to a document is denied an application for review may be lodged with the Office of the Australian Information Commissioner.
The application must be lodged within 60 days from the date the applicant received the internal review decision however an extension of time can be applied for under section 54T of the Freedom of Information Act 1982 (Cth) . However applications must be made within 30 days if they request review of a decision to grant access to documents to another person.
There is no charge for such an application.
See further the OAIC's information on the FOI Review Process.