The United States' next Ambassador to Australia is a highly decorated, at times outspoken naval officer who is no stranger to controversy in the region.

The White House has announced Admiral Harry Harris has been nominated to fill the role that has been empty since September 2016.

The current US Pacific Commander, based in Hawaii, has made headlines in recent years with his hardline approach to China's expansion in the South China Sea.

At one point at a speaking engagement in Australia, after a period of rapid construction of new islands by Beijing in the contested region, Admiral Harris admonished China for "creating a great wall of sand", saying Beijing's behaviour was leading to "serious questions" on its intentions.

The comment — and others — have angered China, which has accused Admiral Harris of "seeking publicity in the region" and "sowing discord".

Both the Coalition and Labor have welcomed the announcement from the White House.

"[Admiral Harris] has visited Australia many times, he's well known to us, he's a highly decorated naval commander, and we look forward to his Senate nomination proceeding," Foreign Minster Julie Bishop said.

Labor's foreign affairs spokeswoman Penny Wong said Admiral Harris had earned the respect of both sides of politics in Australia and the United States.

The Pacific Commander position he has held for almost three years gives him a wealth of knowledge about the region, editor of industry publication Breaking Defence, based in Washington DC, Colin Clark said.

"Harris is not afraid to be undiplomatic because, in many ways, the head of Pacific Command is the most important ambassador in the Pacific — he is the one guy that goes everywhere," Mr Clark said.

On Admiral Harris's knowledge of China, Mr Clark said: "I think Australia is going to be very lucky to have one of the most informed American officials on the country that we've now identified publicly as our chief competitor."

He also said Australia could use Admiral Harris as "cover" should they want to send Beijing a stern message about China's activities in the South China Sea.

Admiral Harry Harris met with Prime Minister Malcolm Turnbull last year. ( AP: Mary Altaffer )

Selection 'shows US places priority on Australia'

Former national security adviser to prime ministers John Howard and Tony Abbott, Andrew Shearer — who is now with the Centre for Strategic and International Studies in Washington — said Admiral Harris is an "outstanding choice" and his selection shows the White House "do place a priority on Australia and the alliance".

He said Admiral Harris has deep connections from the top echelons of Australian politics to the Australian military.

"We know him and he knows us," he said.

Mr Shearer described Admiral Harris as a "down to earth, direct" person who will be well received by Australians and said to describe him as "hardline" on China is not the right description.

"What China's done in the sense of militarising those features in the South China Sea is pretty extraordinary and concerning, and I think it was part of his job as Pacific Commander to call it as he saw it," he said.

He said Admiral Harris knows how to be a diplomat after years interacting with leaders in the Asia Pacific region.

"The idea that he's a bull in a China shop, so to speak, is well wide of the mark," he said.

In a statement, the White House said Admiral Harris is a "combat proven Naval officer with extensive knowledge, leadership and geo-political expertise in the Indo-Pacific region" who has "served in every geographic combatant command and has held seven command assignments" during his 39-year career.

Admiral Harry Harris is well known to both sides of Australian politics. ( AAP: Supplied )

ABC/Reuters