US President Donald Trump announced a 20 per cent levy on cargo ships travelling through the Strait of Hormuz, claiming the United States should be reimbursed for protecting one of the world’s busiest shipping routes.

The announcement has rattled global energy markets, with oil prices jumping around 10 per cent in a day.

Experts warn Australians could soon feel the effects through higher fuel prices and increased costs across the supply chain.

While the NRMA says any increase at the bowser is likely to be gradual, economists warn prolonged disruption could push up the cost of freight, farming supplies and household essentials.

Australia currently holds more than a month’s worth of fuel reserves, with much of its supply arriving via alternative shipping routes.