A quick glance at NZ Part 61 reveals plenty of examples of "...experience acceptable to the director", "flight test acceptable to the director" and the like. I'd rather not have to satisfy our 'director' about anything and just do what it says in the book.
Sounds worse than it is, scavenger. Most countries in the aviation world publish the way that you can satisfy the Director in any particular case. In NZ / FAA etc, it's an AC, Advisory Circular. In Euro-land, it's an AMC, Acceptable Means of Compliance. Basically it involves a document controlled by the CAA rather than the Minister or parliament.
Still sounds scary? It's just a way of reducing volumes of hundreds of pages of legal-speak, strict liability, mumbo-jumbo, to 79 pages of Rules and plus a plain English, accessible-to-pilots, document.
It also means that, in rare cases, if someone comes up with a better way of achieving safe outcomes, it can be approved without rewriting the Rules.