The US Secretary of State, Mike Pompeo, says he's confident South Pacific nations will choose the United States as an ally over China, despite Beijing's growing clout in the region.

Mr Pompeo was speaking after meeting with his Australian counterpart, Julie Bishop who's visiting the US.

Photo: AFP/ via 2018 Getty Images

He said the region is like most places in the world which understand the enormity of having an ally which has consistently projected democratic values.

"The human dignity that comes with having an American partner is different from having partners that aren't quite that way. I think over time that will ultimately prevail, not only in the South Pacific, but all across the world," Mr Pompeo said.

And he said that would ultimately prevail not only in the South Pacific but around the world.

U.S. Defense Secretary James Mattis, who held talks with his Australian counterpart Marise Payne in California, said both the United States and Australia agreed on the need for a free and open Pacific region "where nations large and small are treated with respect for their territorial integrity, for their sovereignty, their sovereign decisions," James Mattis said.

In a joint statement, the countries said they were committed to working together to "shape an Indo-Pacific that is open, inclusive, prosperous, and rules based."

Mattis and Payne also signed a memorandum of understanding to work together to develop software to address cyber and other security threats.

The agreement comes amid efforts by Australia to ramp up diplomacy in the Pacific to combat China's rising influence. In June, Australia promised to bolster the cyber security capability of Pacific island nation Vanuatu as part of a negotiation on a security treaty with its neighbour.

Reuters