Australia's ambassador to the US, former treasurer Joe Hockey, has praised the Trump administration as a "practical" and "credible" force that is finding its feet 70 days into its four-year term, and called for a halt to "constant" criticism of the White House.

In his first major speech to an Australian audience since Donald Trump took office, Mr Hockey said the Republican's rise reflected a citizenry that felt "impotent" and heralded "the arrival of disruption into the mainstream of American politics".

He implored critics to give the unorthodox but "practical" administration a fair go, noted many Americans backed the President's unprecedented attacks on the media, and predicted the failure to repeal Obamacare would not harm Mr Trump.

"We need to avoid the temptation to become constant critics of the new US administration because it is not a carbon copy of the previous administrations," Mr Hockey told The Sydney Institute on Thursday night.