A draft defence bill tabled in the US Senate last month outlines that more than $300 million has been allocated for naval construction in Darwin, the ABC has reported.

The Australian Defence Department reportedly told the ABC that the proposed funding still has to be approved by Congress, but insists that any military projects are negotiated and agreed to by both governments.

Last month Defence and NT Chief Minister Michael Gunner rejected claims a top secret naval port is in the works at Glyde Point, north of Darwin, which could eventually help US Marines operate more readily in the Indo-Pacific.