The National Interest Analysis (NIA) assesses the CPTPP from the perspective of its impact on New Zealand and New Zealanders. It includes economic modelling to quantify the costs and benefits.

Every time the New Zealand government signs a new significant international treaty, a National Interest Analysis (NIA) is produced by the lead government agency. The NIA is then presented to Parliament, together with the text of the treaty, for consideration.

For CPTPP, the NIA was released on 21 February 2018. The NIA scrutinises the agreement, weighing up the costs and benefits of New Zealand signing up to CPTPP.

The National Interest Analysis was updated on 9 March 2018 with more details of side letters that were signed along with the agreement.

Separate NIAs were presented to Parliament in 2017 for the four other treaties that New Zealand will be required to ratify as part of CPTPP.