An offer of guaranteed access to Australia’s critical minerals in return for sparing the country’s steel and aluminium exports from tariffs was rejected by the Trump administration, but the government will persist with using the resources as a bargaining chip in ongoing negotiations.

With the government continuing to push its case in a bid to ward off a second wave of tariffs on products such as meat and pharmaceuticals, sources familiar with the process said the proposition involving critical minerals was rejected on the weekend when ambassador Kevin Rudd met US Commerce Secretary Howard Lutnick and sought an exemption from the metals tariffs.