COALITION Senator Cory Bernardi has started a Twitter row after he posted a selfie while wearing a Donald Trump-style hat, with a controversial message.

The South Australian MP, who is on secondment in the US representing Australia at the United Nations, posted a photograph of himself with the hat that had the words: “Make Australia great again”.

The message is an adaptation of the message Trump has worn on his hat he wears, which always states: “Make America great again.”  The social media controversy comes after last week, when Senator Penny Wong called on Prime Minister Malcolm Turnbull to pull Senator Bernardi into line over his comments about Trump.

The Liberal senator said the Republican nominee was the “least bad candidate”.

“Unlike most of my colleagues Down Under, I’ll be cheering on a Trump victory,” he wrote on Wednesday in his weekly newsletter.

“I hope there’ll be something to celebrate.”

Senator Bernardi said Trump was unorthodox, deeply flawed and somewhat erratic, but has tapped into a deep well of discontent in the US.

“I disagree with a number of his policy positions but there’s a lot of what he is saying that I do agree with,” the South Australian senator said.

“The hostility with which he has been treated by sections of the media, some political insiders and the militant left only reinforces the need for change.”

Democrat candidate Hillary Clinton, on the other hand, is the poster child for everything that is wrong with the American political system, he said.

One Nation Senator Malcolm Roberts went one step further and echoed Trump’s call for her to be jailed.