One Nation MP David Farley crossed the floor on 23 June 2026 to vote alongside the Greens and teal independents in favour of capping the fuel tax credit scheme for the most profitable mining companies — a defection that has fractured the minor party's internal discipline and drawn a public broadside from Senator Matt Canavan.

The fuel tax credit scheme permits businesses operating heavy diesel equipment to claim refunds on the excise component embedded in their fuel costs. For large miners, the sums are substantial. The Guardian reported on 22 June 2026 that BHP alone received $622 million in diesel fuel tax credits in the last financial year. The measure Farley supported would place a ceiling on those credits for companies at the top of the profitability curve, a targeted restriction rather than a blanket repeal of the scheme.

The legislative backdrop matters. The Treasury Laws Amendment (Fuel Excise Relief) Bill 2026 amends both the Customs Tariff Act 1995 and the Excise Tariff Act 1921 to temporarily reduce excise duty rates and excise-equivalent customs duty rates on fuels. The ATO's published rate schedule confirms that fuel tax credit rates were cut by 60.9% for the period 1 July 2025 to 30 June 2026 as a direct consequence of those changes to the underlying excise duty. That reduction has already compressed the value of credits across the board; the Farley vote extends the debate into whether the residual credits flowing to high-margin miners warrant further restriction.

Canavan told reporters on 24 June 2026 that Pauline Hanson had lost control of her MPs. The comment is pointed: One Nation has historically positioned itself as a bulwark against what it frames as elite-driven economic interference, and its base includes regional communities economically intertwined with the resources sector. A vote that constrains mining tax relief sits awkwardly with that positioning, whatever the fiscal logic behind it.

Farley, a new MP, has not yet established a long voting record against which to read the defection. Whether this is idiosyncratic positioning — rooted in his own constituency calculus or a reading of the populist arithmetic on mining mega-profits — or the start of a more persistent independence from the party line is not yet clear. What is clear is that the Greens and teals secured a crossbench majority on the specific question of capping credits for the most profitable miners, and that they did so with support from within a party formally opposed to their broader platform.

The fiscal stakes are not trivial. If BHP's $622 million figure is representative of the order of magnitude flowing to major miners, a legislated cap could redirect hundreds of millions in annual revenue back to the Commonwealth — or, depending on scheme design, simply leave it unclaimed. The resources sector will contest any cap vigorously; the standard industry argument is that diesel fuel tax credits offset a tax on a productive input, not a subsidy in the conventional sense, and that distorting their availability raises costs that flow through to project economics and, ultimately, employment in resource-dependent regions.

That argument carries weight in certain electorates. It also explains why One Nation, which draws disproportionate support from regional Queensland and Western Australia, would ordinarily be expected to resist any restriction on credits the mining sector values. Farley's vote cuts against that grain, and Canavan's public rebuke is as much a signal to the broader party base as it is a criticism of one MP.

The immediate question for One Nation is whether Hanson moves to discipline Farley or absorbs the breach and moves on. The answer will say something concrete about the party's internal governance and its capacity to hold a coherent legislative position as a crossbench actor in what appears to be an increasingly fragmented Senate arithmetic.