Foreign Minister Julie Bishop hopes Rex Tillerson stays on as the US secretary of state.
Reports have emerged that President Donald Trump is planning to oust Mr Tillerson and replace him with CIA director Mike Pompeo.
Ms Bishop says she has formed a very close personal and professional working relationship with Mr Tillerson and would be "very sorry" to see him go.
"I think he has represented the United States' interests exceedingly well, particularly in our region," she told Sky News on Friday.
"I would hope that he would stay on. He's built up a lot of trust and respect in Australia and the Indo-Pacific."
The deputy Liberal leader has met Mr Pompeo and has had "very productive" and constructive discussions with him in his current role.
"I feel sure that I could work closely with whomever the United States administration determines should be the secretary of state," she said.
White House spokeswoman Sarah Sanders said Mr Tillerson was still secretary of state.
"There are no personnel announcements at this time. Secretary Tillerson continues to lead the State Department and the entire cabinet is focused on completing this incredibly successful first year of President Trump's administration," she said in a statement.
