Hmmm . . . I honestly can't see how having your main lights on or off is going to make any difference in the legality of fog lights (although there is a passage in the road rule about being able to turn off your main lights if you have functional fog lights - in fog. This might be a ploy to try and convince police they are fog lights rather than "Driving lights" which are definitely illegal near other traffic ).
That said, afaik
, fog lights are illegal to have on unless there are "inclement conditions" ( i.e. fog or rain ).
In any case, just *don't* be like f***** SS commodore owners who run with them on all day, every day, with every last one of them pointing upwards and blinding you . . .