Strengthening ties with America, Japan and India creates a "strategic balance", Prime Minister Scott Morrison says, as Australia and the US signed a secret 10-year agreement on defence co-operation to "deter coercive acts and the use of force" in the Indo-Pacific amid rising tensions with China.

The agreement, signed at the AUSMIN talks between Australian and US foreign affairs and defence officials on Tuesday in Washington (Wednesday AEST), paves the way potentially for a stronger American military presence in Australia, including establishing a strategic fuel reserve in Darwin and carrying out maintenance on US hardware such as aircraft.