Richest Kiwis pay about half as much on the $ as the rest of us

[king1]

Another scenario to add to the "why fairness can never be objectively defined):

I've two friends who were earning around $300K each.  Tax on $300K is $97K.  Last year, one of the two decided to take a career "gap year" and just lived off savings/overdraft for the whole year, so he didn't pay any income tax at all (he probably paid a small amount on his investment income, but it would have been less than $1K all up).  They both still used public services, their kids went to school, doctor etc. and yet one contributed $97K in income tax and the other next to nothing; is it fair that the those that choose to work have to subsidise the ones that chooses not to?

on that one I would say fairness doesn't come into it.  The 'fairness' aspect is only taken into account during the policy setting phase.  After that the only criteria considered are the current tax rules... 

the friend having a gap year will be paying a share of taxes in GST anyway...

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Edit:
and I guess the other point is, the friend will only get away with not working for so long before he runs out of money, reduced quality of life, frugal spending etc - so from that POV it could be considered 'fair'

and I feel there is a problem in your argument when you use the word "subsidise " - subsidising implies the entitlements of one directly affects the liabilities of another, which is just not the case. With taxation policy you are either liable or not - with government subsidies you are either entitled or not - the actions, entitlements or liabilities of any other individual has no bearing...