It really depends on
how one chooses to demonstrate their eligibility for a Permanent Resident Visa or a variation of travel conditions.
For a lot of the criteria, INZ are able to simply check their own records. This includes checking that a Resident Visa is held, and for the requisite length of time if required by relevant instructions (e.g.
RV2.5(a) and RV2.5(b) for a PRV;
RV3.5(b) for a 12 month VOC), and checking that one has met their Section 49(1) conditions if applicable.
Most notably, if the applicant chooses to demonstrate a commitment to New Zealand by means of significant time spent in New Zealand (
RV2.5.1 for a PRV;
RV3.5.1 for a 12 month VOC), evidence of this does not have to be provided to INZ. INZ already has records of people's movements across the New Zealand border (in both directions), so they'll simply check against those. (If you're interested, you can request a copy of these records
here.) However, if the applicant chooses to demonstrate a commitment to New Zealand in any other way, actual evidence of this commitment will need to be provided; the
INZ 1176 guide (Guide for Resident and Former Resident Visa Holders to enter New Zealand as a resident) has more information on this.
For character checks (PRV only as per
RV2.5(e); there are no character requirements for a VOC), INZ is usually only interested in the applicant's New Zealand character records, and they obtain these directly from the Ministry of Justice. If you think about it, it makes sense: the holder of a Resident Visa would normally spend significant time in New Zealand so would have little opportunity or reason to create a character defect in their country of origin, and the character check against country of origin would have already been done when applying for the original Resident Visa. The generic immigration instructions pertaining to character checks specifically mention that holders of a Resident Visa applying for a Permanent Resident Visa under RV2 do not usually need to submit a foreign police certificate, but gives INZ discretion to request one anyway should it be believed necessary (
A5.5(b)).