This might help.
Extract from the NSW regs:
includes the following:
(a) campervans,
(b) caravans,
(c) holiday vans,
(d) park vans,
(e) annexes,
(f) associated structures,
(g) any other type of van or portable device used for human habitation,
but does not include:
(h) a tent or structure that has two or more walls and a roof or ceiling primarily constructed of flexible fabric or plastic material, or
Extract from the Vic regs are less precise as a camper trailer IS a movable dwelling.
The owner of a movable dwelling, other than a flexible annexe or tent, in a caravan park, must ensure that a smoke alarm that complies with Part 3.7.2.2(b) of Volume Two of the BCA is installed in the dwelling.