Tax and KiwiSaver
You'll be happy to hear that your KiwiSaver nestegg is tax free at the time of the withdrawal. That's because it will have been taxed along the way during your investment period. The amount of tax you'll have paid will depend on what you are invested in, (different investments and funds are taxed at various rates) and also your prescribed investment rate or PIR. Your PIR is tied to your taxable income.
You can read more about PIR rates here on Inland Revenue's website, but in brief there are three rates: 10.5%, 17.5% and 28% and they roughly align to marginal rates.
As of April this year, your employer contributions also became subject to tax as well; employer superannuation contribution tax. ESCT varies according to your earnings and ranges from 10.5% to 33%.
|$0 to $16,800||10.5%|
|$16,801 to $57,600||17.5%|
|$57,601 to $84,000||30%|
Your KiwiSaver statement should have a breakdown of your fees and taxes paid although there is currently no consistency in the way that's reported among providers. That will change next year when legislative changes take effect with respect to reporting and disclosure regulations.
Going back to your original question, the short answer is no. You've already paid your dues.
If you are planning on keeping your money invested past the age of 65, it is possible to do so. The terms and conditions vary according to provider so check with yours if you're keen on going that route.