The imposition of punitive trade restrictions by China has taught Australian exporters to diversify their markets, leaving them well-prepared to deal with any tariffs imposed by the Trump administration, Trade Minister Don Farrell says.

While insisting there were no grounds for the US to apply 25 per cent tariffs to Australian steel and aluminium, Senator Farrell said aluminium and steel exports to the US had already fallen in the past 12 months as exporters found better markets.