The Communist Party of New Zealand (CPNZ) was a communist party in New Zealand which existed from 1921 to 1994. Although spurred to life by events in Soviet Russia in the aftermath of World War I, the party had roots in pre-existing revolutionary socialist and syndicalist organisations, including in particular the independent Wellington Socialist Party, supporters of the Industrial Workers of the World in the Auckland region, and a network of impossiblist study groups of miners on the west coast of the South Island.

The Communist Party of Australia (CPA), known as the Australian Communist Party (ACP) from 1944 to 1951, was an Australian communist party founded in 1920. The party existed until roughly 1991, with its membership and influence having been in a steady decline since its peak in 1945. Like most communist parties in the West, the party was heavily involved in the labour movement and the trade unions. Its membership, popularity and influence grew significantly during most of the interwar period before reaching its climax in 1945, where the party achieved a membership of slightly above 22,000 members. Although the party did not achieve a federal MP, Fred Paterson was elected to the Parliament of Queensland at the 1944 state election. He won re-election in 1947 before the seat was abolished. The party also held office in over a dozen local government areas across New South Wales and Queensland.