Relevant portion of the Arms Regulations 1992 for those who are interested
In addition to the condition in subclause (1)(b) relating to ammunition, ammu‐
nition must be stored—
(a) in its own secure storage container (such as a cash box or an ammunition
box that is in secure storage or in a stout locked cupboard) that has—
(i) a locking mechanism that has a key or combination number that
is different from the key or combination number for the person’s
container for firearms; or
(ii) a padlock that has a key or combination number that is different
from the key or combination number for the person’s container for
firearms; or
(b) in a lock box in a gun safe cabinet that has a different key from the key
for the gun safe cabinet, and the key for the gun safe cabinet must be
stored in a different place from the other key; or
(c) if the ammunition is bulky and difficult to store in a container, in a
locked room or storage area on the licence holder’s premises that—
(i) is of sufficiently robust construction to prevent the theft of the
ammunition; and
(ii) has been inspected and approved by a member of the Police
When renewing I had a funny experience with the ammo safe. Had a padlocked/deadbolted cupboard which I used (one may have described it as "stout"), well separate from safe. Not up to snuff, needs to be a locked container. My reckons about someone being able to abscond with a container easier than a cupboard were brushed aside. In any case I bought some ammo tins, padlocked them, and now they go in the locked cupboard. I don't really know if that was the correct application of the regulations but as @
m101a1 said, no point arguing when it cost me $50 to do it their way.