This is a trifle simplistic - the African link is to Aborigines as it is to Europeans or Chinese.
There’s also the landmass: Australia is 7,686,850 sq km (approaching the US’s 9,631,420 sq km in size), while NZ is a mere 268,680.
Australia is vast, and most of the 20 million population is very sparsely distributed, congregated on the coast, the most populous of which is the east coast. There’s rainforest and temperate, but a huge amount of the middle is desert.
New Zealand is relatively small, with the 4 million population somewhat more evenly distributed, though more concentrated on North Island and north of South Island.
Going on personal experience of travelling around east coast Australia, versus most of New Zealand, Kiwis were much more welcoming and accommodating, without the standoffish nature of most of the people we met outside of Sydney and Canberra.
The distinction in how the indigenous inhabitants are regarded is stark; though I met a couple of deeply racist white Kiwis, generally whites seemed quite benevolently predisposed towards the Maori culture; whereas the antipathetic indifference for the aborigines in Australia amongst pretty much everyone was stark.
Sorry Aussies, I really enjoyed visiting your country, and met some great and kind people there, but I genuinely found New Zealand personally much more charming.
Simple way to tell the accents apart, remember that Aussies say “feesh and cheeps”, while Kiwis say “fush and chups”.