CANBERRA — Lobbying firms in Australia are widening their political networks as Pauline Hanson’s One Nation gains ground, challenging an assumption that influence in Canberra runs mainly through the country’s two major parties. Hanson addressed the Australian Chamber of Commerce and Industry’s annual business summit earlier this month, her first speech to the gathering. ACCI chief executive Andrew McKellar said the party “can’t be ignored.” Lobbyists say business interest in One Nation has grown over recent months, following stronger polling and the party’s victory in a federal by-election in Farrer in May. Some firms are now describing their approach as “multipartisan,” reflecting the possibility that clients may need access to a broader range of political players. The shift comes as One Nation, founded 30 years ago, seeks a larger role in a political system long dominated by two major parties. Polling cited in recent coverage put the party’s primary vote between 20 and 36 percent, depending on the state. The next test is the Victorian state election on Nov. 28. The result will show whether favorable polling can be converted into parliamentary representation. One Nation is also preparing for New South Wales’ state election in March. For companies and lobbyists, the stakes are practical: a party with seats or greater leverage could shape policy debates and the business community’s access to decision-makers. For voters, the campaign will offer a measure of whether One Nation’s growing support is a lasting political realignment or a polling surge that fails to deliver at the ballot box.