The Politz will probably overlook such a detail as it falls under the Dangerous Goods Regs and not the Firearms Act...although they can still enforce the regs (worksafe are the licensing authority for explosives and dangerous goods)
Dangerous Goods (Explosives) Regulations 2011:
http://www.legislation.vic.gov.au/domino/Web_Notes/LDMS/LTObject_Store/ltobjst8.nsf/DDE300B846EED9C7CA257616000A3571/BF31ADBD9B794DBFCA257C78001872F8/$FILE/11-37sra005%20authorised.pdf69 Explosives not to be stored in safes or refrigerators A person who stores any explosives, except explosives of Classification Code 1.4S, must not store the explosives in a document safe, money safe or refrigerator.
70 Storage of Hazard Division 1.1, 1.2, [b]1.3, 1.5 or 1.6 explosives[/b]
(1) A person who stores explosives of Hazard Division 1.1, 1.2, 1.3, 1.5 or 1.6 must—
(a) store the explosives in— (i) a receptacle that complies with regulation 73; and
(ii) a building that complies with regulation 63(1)(b); and .....
73 Requirements for construction of receptaclesA receptacle used for the storage of explosives must be constructed and maintained as follows—
(a) the construction of the receptacle must be sturdy; and
(b) the receptacle must have a close fitting closure; and
(c) the inner construction of the receptacle must—
(i) be made from, or be lined with, plywood or close joined timber or another suitable non-sparking material; and
(ii) not include exposed iron or steel.