I’ve found that the motto of New South Wales is “Orta recens, quam pura nites”, i.e. “Newly risen, how pure (or how brightly) you shine!”. The crest of the coat of arms is a rising sun.
If the inscription is worn or obscured, could the words possibly be these? A public building like a courthouse might well have the state motto on it (just as French public buildings are invariably adorned with “Liberté, égalité, fraternité”).
I agree that “altra” and “regin” don’t make any sense as they stand. If the inscription is an adaptation of the motto, I can only suggest that it might be “Alta regina” (“Lofty queen”).
_________________________
Dilige et quod vis fac