I don't think you need too much at retirement, assuming you get the Government super. There is a nifty retirement calculator at the GMI website. If you have a paid for house, you could live a simple but comfortable life with maybe 200K invested in low fee funds in addition to the pension. Have a play around with this:
For something a little more in-depth, I have countless hours of fun with the FIRE (Financial Independence Retire Early) simulator.
Just on net worth in NZ, the most recent survey was produced last year. The graph referenced earlier in the thread was from 2001 (update below)
[Mod edit: clickable short Stats link]
But depending on where you live a house or apartment is likely to be worth at least $400k, so if you add $200k of managed funds then that's a net worth of $600k+. That is much higher than the net worth figures for the 55+ age brackets on the graph, which makes me wonder just how many people of my generation are realistically going to be able to survive in retirement.