Answer:
Both are part of the Commonwealth; both were previously of the British Empire; both have relatively short histories of European contact; both have long histories of indigenous population; both have histories of oppression of those indigenous populations; both use real English as their official language; both have proper accents; both are democratically run; both are common law countries; both are very well-ranked in many major sports; both are in the Southern hemisphere; both are on the Indo-Australian tectonic plate.