Why did Sir Edmund Hillary get his face on the five dollar bill in NZ?

In 1992 Hillary appeared on the updated New Zealand $5 note, thus making him the only New Zealander to appear on a banknote during his or her lifetime, in defiance of the established convention for banknotes of using only depictions of deceased individuals, and current heads of state. The Reserve Bank governor at the time, Don Brash, had originally intended to use a deceased sportsperson on the $5 note but could not find a suitable candidate. Instead he broke with convention by requesting and receiving Hillary's permission - along with an insistence from Hillary to use Aoraki/Mount Cook rather than Mount Everest in the backdrop.