An appraisal, also known as a CMA (Comparative Market Analysis), provides a relevant review of the value of a property and is generally provided by a Real Estate Agent as part of the process to market and sell a home. It will note recent sales in the area that are comparitive based on a number of factors such as property size, house size including number of rooms, bathrooms, location, quality, current council valuation.
An appraisal is not a 'valuation' and is not accepted by lenders for this purpose. To produce a 'valuation' on land or property for the public, the person providing it must be a registered and certified public valuer under the Valuers Act 1948.
Lenders have other options that are used for assessment such as electronic and council valuations. They may also request a 3rd party to provide a full registered valuation. If a registered valuation has been requested, it is best to ensure this is done via the Lender's preferred panel and not directly.
Learn more about NZ's property valuation standards on the LINZ website.