Western Australia (Australia) is 9.5 times larger than New Zealand.
Area: 267,710 km2 World Factbook
Population: 4,401,916 (July 2014) World Factbook
New Zealand is an Oceanian island country in the southwestern Pacific Ocean. The country geographically comprises two main landmasses – that of the North Island, or Te Ika-a-Māui, and the South Island, or Te Waipounamu – and numerous smaller islands. Wikipedia
Western Australia is a state occupying the entire western third of Australia. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Southern Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east. Wikipedia