http://nz.hudson.com/salary-hub/salary-calculator
http://www.payscale.com/research/NZ/...Zealand/Salary
Those are two websites I found by Googling. I've no idea where INZ would check these things.
Some forum members have had the rate of pay being offered them queried by INZ, and have been able to answer by showing similar jobs advertised in that geographical area, for a similar salary. When INZ look at the salary, it is part of checking that the applicant genuinely has a skilled job. There have been cases when some employer, trying to "help" an applicant, has given them a false job description of some highly skilled role, but if they are then paid in line with the entry-level job they are really doing, it shows up the fraud.