I’ll side that it is one of many, many overreaches when governments can lodge fines. In this case government hangs its hat on
ROAD SAFETY ROAD RULES 2017 - REG 13
What is a road related area
(1) A “road related area” is any of the following
(a) an area that divides a road;
(b) a footpath or nature strip adjacent to a road;
(/c) an area that is not a road and that is open to the public and designated for use by cyclists or animals;
(d) an area that is not a road and that is open to or used by the public for driving, riding or parking motor vehicles;
(e) a place that is a road related area by virtue of a declaration under section 3(2)(a) of the Road Safety Act 1986 —
but does not include a place that is not a road related area by virtue of a declaration under section 3(2)(a) of the Road Safety Act 1986 .
Note
Motor vehicle is defined in the Road Safety Act 1986 .
(2) A reference in these Rules (except in this Division) to a road related area includes a reference to any part of a road that is a shoulder of the road.
Note
Shoulder is defined in rule 12.
Impressive cross referencing too!