One Nation has scored a major upset in the Western Australian state by-election for Secret Harbour, a seat that had been considered safe Labor territory in Perth's outer mortgage belt. The result follows a similarly striking win in the federal seat of Farrer earlier this year, suggesting One Nation's appeal now extends well beyond its traditional base of disaffected conservative voters and into working and middle-class communities that have historically backed Labor.

Labor's primary vote in Secret Harbour collapsed from 46.5 per cent to 24.4 per cent, while One Nation's candidate, Luke Herdegen, surged from 8.4 per cent to 39.1 per cent, with the Liberals trailing in third on 17.3 per cent; One Nation now leads on preferences, though Labor has not yet conceded pending postal votes. The seat overlaps federal Liberal MP Andrew Hastie's electorate of Canning and Labor MP Madeleine King's seat of Brand, raising fears for both major parties, while Prime Minister Anthony Albanese, whose 2022 and 2025 election wins relied heavily on WA support, faces a warning sign despite his government's efforts to safeguard the state's GST deal.