There are a number of financial planning issues that you need to be aware of when returning to live in New Zealand, and I have posted a comment for each different topic, see the links below in this post.
For NZ Superannuation, the issues you need to be aware of are:
1. Eligibility - there is a residency requirement for entitlement to NZ Superannuation. This link will assist you:http://www.workandincome.govt.nz/individuals/65-years-or-older/superannuation/superanuation-overview.html
2. NZ Superannuation income and asset offsets. NZ is one of the few countries that does not 'asset', 'income' or 'means' test your income from the state pension. This means that you are entitled to receive this income if you are eligible (see point 1), regardless of how many assets you have or income you have. However, the exception is if you have specified superannuation or pensions from an overseas country. There is a facility for pensions received from other countries to be offset against NZ superannuation income.
This has caused quite a lot of controversy in NZ and it does not look like there is a solution forthcoming in the forseeable future. This link will assist you: http://www.nzpensionprotest.com/Home/media-coverage/scoop-in-2007 (a website dedicated to this issue. OR (this is a 25 page IRD document http://www.ird.govt.nz/resources/7/6/7643cb004bbe4247b50df5bc87554a30/tib5-13.pdf)
3. Age of eligibility for NZ Super. This is currently age 65. There have been numerous calls for the age of eligibility to be increased, the politicians currently in Government have said that they will not move it, but the oppositions policy plank is to raise the age of eligibility. This link provides you with more information: http://www.stuff.co.nz/dominion-post/news/politics/7081932/Key-rules-out-pension-age-referendum
These are all things that you need to take into account when planning your retirement to NZ. There are a number of other issues, which I have outlined in posts relating to taxation issues, KiwiSaver and insurance.
Personal Superannuation issues
By Carey Church