Foreign Minister Penny Wong is preparing to meet the new US Secretary of State, Marco Rubio.

Wong attended the inauguration of President Donald Trump in Washington, and will join other foreign ministers from the Quad group for talks with Donald Trump’s top diplomat on Wednesday (AEDT).

The Quad comprises Australia, the US, India and Japan, representing nearly 2 billion people.

Ahead of the meeting, Wong called bilateral ties with the US “our most important strategic relationship” and said she was happy a meeting of the Quad nations was being held so soon after the inauguration.

“It’s a demonstration of the collective commitment of all countries to the Quad, an iron-clad commitment in this time where close co-operation in the Indo-Pacific is so important,” she said..

Rubio is also expected to hold separate talks with Wong and the other foreign ministers over the coming hours.

The Quad was established in 2007 to bring together countries that had worked together in response to the devastating 2004 earthquake and tsunami in the Indian Ocean. Its members stress its diplomatic nature and broad focus on regional issues including infrastructure, humanitarian aid, disaster relief, climate change and maritime security.

Even though security is only part of the mix, the Quad is a major component of the American strategy to counter China’s growing assertiveness and vast territorial claims in the region, including to virtually all of the strategically important South China Sea and the democratic self-governing island of Taiwan.

For his part, Rubio called China “the most potent, dangerous and near-peer adversary this nation has ever confronted” during his confirmation hearing last week, and the issues that gave rise to the rebirth of the Quad in Trump’s first term have only intensified.

Among other things, China has been pursuing its regional territorial claims more aggressively, leading to direct confrontations with the Philippines and others, and working toward establishing a true “blue-water” navy capable of operating in seas far from China, including advancing toward the construction of nuclear-powered aircraft carriers, in a growing global challenge.