I think this is the Australian legislation you have in mind,...

I think this is the Australian legislation you have in mind, 383hq.

BANKING ACT 1959 - SECT 42
Delivery of gold
(1) Subject to this Part, a person who has any gold in the person's possession or under the person's control, not being:
(a) gold coins the total value of the gold content of which does not exceed the prescribed amount; or
(b) gold lawfully in the possession of that person for the purpose of being worked or used by that person in connexion with the person's profession or trade;
shall deliver the gold to the Reserve Bank, or as prescribed, within one month after the gold comes into the person's possession or under the person's control or, if the gold is in the person's possession or under the person's control on any date on which this Part comes into operation, within one month after that date.
(1A) A person is guilty of an offence if:
(a) the person fails to comply with subsection (1); and
(c) there is no instrument in force under section 48 exempting the person from the application of this subsection.
Penalty: 50 penalty units.
Note 1: Chapter 2 of the Criminal Code sets out the general principles of criminal responsibility.
Note 2: If a body corporate is convicted of an offence against this subsection, subsection 4B(3) of the Crimes Act 1914 allows a court to impose a fine of up to 5 times the penalty stated above.
(2) Where a person who has gold lawfully in the person's possession for the purpose of being worked or used by the person in connexion with the person's profession or trade ceases to have that purpose in respect of that gold, the person shall deliver the gold to the Reserve Bank, or as prescribed, within one month after the person has ceased to have that purpose in respect of that gold.
(3) A person is guilty of an offence if:
(a) the person fails to comply with subsection (2); and
(c) there is no instrument in force under section 48 exempting the person from the application of this subsection.
Penalty: 50 penalty units.

Hmm... what to do now? R.