The Morrison government has swung its support behind the Trump administration's push to forge a new alliance of democracies to counter China's muscular ambitions, saying it could be built on the close Australia-US relationship.

At the annual AUSMIN meeting in Washington, the quartet of Australian and US foreign and defence ministers also said they'd step up cooperation on developing new defence technologies in areas such as hypersonics, establish a US strategic military fuel reserve in Darwin, and create a joint taskforce to counter harmful disinformation.