An assessor's scope determines the qualifications they can assess. We work with the industry to determine the assessor-specific requirements (ASRs) for each qualification.
Most of the time, an assessor needs to hold the NZQA qualification or current unit standard (or be able to demonstrate equivalent skills and knowledge) at the same level, and preferably a level above, that at which they will be assessing. In some cases, assessors need to meet certain other requirements, and these depend on the qualification.
You'll also need to reference the ASRs if you're going for a scope extension. Don't forget, you can't assess a unit standard or qualification that is not in your scope.