Aust worried about Chinese military base

Australia's foreign affairs department is not complacent when it comes to the prospects of a foreign military base in the Pacific region.

Frances Adamson says Australia is not complacent on a Chinese military base in the Pacific. (AAP)

Despite assurances that Vanuatu has ruled out allowing China to build a military base on its shores, Australian diplomats aren't complacent.

China is building a wharf in Vanuatu funded by a concessional loan and in April there were reports it was seeking a military base. Beijing dubbed the reports "sheer fiction".

Department of Foreign Affairs and Trade official Daniel Sloper told a Senate estimates hearing there were concerns any potential bases could lead to strategic competition in a region that doesn't experience that at present.

Secretary Frances Adamson said there were concerns it could also lead to a direct military threat to Australia.

The job of diplomats was to ensure the region remains peaceful and uncontested and that the "distant prospect of a foreign military base" in the Pacific remains that way, Ms Adamson said.

Asked if she considers it distant: "We never want to be complacent about these things".