ABC political editor Chris Uhlmann has explained his viral critique of US President Donald Trump in an interview on American television, telling news anchors that yes, the country is losing its grip on its position as the world's leader.

News network MSNBC called his claims "extraordinary", and questioned whether that was really the message that came out of the G20 gathering.

"It was certainly the way I saw it and it's the way that a lot of other delegations saw it as we had conversations obviously around what was going on at the G20," Uhlmann said.

In a weekend report that has now gone viral, Uhlmann said Mr Trump's "awkward" performance at the G20 summit in Germany showed he had "neither the desire nor the capacity to lead the world".

He said the US President was seeking to turn his nation inward and likened him to a character from America's wild west — "a travelling medicine showman selling moonshine remedies that will kill the patient".

Sorry, this video has expired Chris Uhlmann's report about US President Donald Trump at the G20 went viral

On MSNBC's Velshi & Ruhle show overnight, anchor Ali Velshi questioned Uhlmann about his comments that the "real" and "unscripted" Mr Trump was the one who was "barking out bile" on Twitter.

"How much weight do you and others in the world give to those messages versus what you believe America to actually stand for?" he asked.

Uhlmann described the President's tweets as a "window into his soul".

"Isn't this the unvarnished Donald Trump? Isn't this the way that we see into what the President really cares about?

"And when we see in Australia that the President of the United States spends some time, any time at all, taking issue with a couple of reporters in the United States, you wonder about what his priorities are.

"That is a reasonable thing for people to make a judgement on."