As of 16 June 2016, the new Biosecurity Act 2015 replaced the existing Quarantine Act 1908.

Under the Quarantine Act 1908, it was possible to apply for an import permit for goods that had already landed in Australia.  However, under the new Act, this is no longer possible.  If an import permit has not been issued prior to arrival of the consignment in Australia, you will not be able to obtain one.