US President Donald Trump is demanding that the US' allies massively boost defence spending, and US Defense Secretary Pete Hegseth says a Chinese invasion of Taiwan could be ‘imminent’.

At the same time, the United Kingdom, one of Australia’s closest allies, is rushing to invest billions of dollars in its defence force to make sure it’s ‘war ready’.

USSC Director of Foreign Policy and Defence Professor Peter Dean spoke with ABC News Daily on what that all means for Australia and whether Australia's defence force is fit for purpose.