Injecting fresh energy into a pre-budget campaign to deliver a less-generous fuel rebate scheme, Dr Forrest called it a "long-running joke" preventing the broader mining industry from embracing electrification and clean energy.
"What we need is help right now for the struggling mums and dads of Australia, that $2.5 billion doesn't need to go to people who just made $35 billion last year," he told reporters at the Smart Energy Council conference in Sydney.
"It's a joke."
The scheme gives tax credits to businesses for their use of diesel in vehicles, machinery, plants and equipment on private land, and is claimed in industries including mining, transport, farming, forestry and fishing.
Costing roughly $11 billion a year and no longer tied to the costs of maintaining roads, critics argue the rebates are burdening the budget and keeping users hooked on an emissions-intensive fuel that leaves them vulnerable to supply chain shocks, as exposed by war in the Middle East.
The policy has received renewed scrutiny heading into the 2026 federal budget, with the Australian Council of Trade Unions and the Labor Environmental Action Network among supporters of a less generous scheme.
Fortescue has also been pushing for a wind back. The miner is among the biggest beneficiaries, but is pursuing a rapid decarbonisation agenda to run its trucks and machines on renewable energy rather than diesel.
The iron ore producer claims to be on track to reach "real zero" by 2030, referring to actual emissions cuts without offsets.
Dr Forrest highlighted growing public support for winding back the fuel tax credit scheme when queried if federal government interest had tempered since Israel and the United States attacked Iran.
A few different models have been discussed and the Fortescue founder has specifically been advocating for a $50 million a year cap per corporate group, a change that would save the budget $2.5 billion a year while insulating farmers and smaller operators.
Federal Resources Minister Madeleine King has previously said the government is not considering changes to fuel credits in the 2026 budget and defended their use by farmers, miners and tourism operators not using public roads
