IQA
IS the full assessment obtained from NZQA. This is the only assessment that is recognized by INZ. NZQA is a body set up by the NZ government tasked with assessing educational courses, both within NZ and from overseas.
The sort of statement you get from NZQA with an IQA assessment, if it is equivalent, or comparable (and it doesn't matter what word I used, because it's what NZQA says that matters) is "Your bachelor of (whatever subject)...has been compared to A bachelor of (whatever subject) degree at level 7 -360 credits in New Zealand. This is a specified outcome. This means your qualification is substantially similar to the NZ qualification listed in the assessment outcome."
The applicant has to find the job
description under ANZSCO which best fits their career to date, and work experience, and put the career thus described on their EOI as the skill they are offering to bring to the NZ job market.
To prove they are qualified and skilled in that career, they have to show the qualifications as on the skills checker page.
http://skillshortages.immigration.govt.nz/ If they don't need bonus points, they can look under the List of skilled occupations bar, and the qualifications there, which often mention the ANZSCO description will apply. If they do need bonus points (and that will be most people without a skilled job or offer of one in NZ), they need to look at the qualifications under LTSSL. Having the right qualifications to prove LTSSL is the gateway to bonus points, both for the qualification and for work experience.
When looking at ANZSCO, both Quantity Surveyor and Civil Engineer come under the section Civil Engineering Professionals.
http://www.abs.gov.au/ausstats/abs@....+Professionals It doesn't imply that they're the same job, that they come under the same section. ANZSCO and INZ would recognize that they are jobs that need the same general kind of knowledge, but also that workers in the two jobs would each have their own specialisms, as mentioned in the two ANZSCO listings.