SYDNEY: Australian Home Minister Clare O'Neil on Thursday called Donald Trump Jr. a "big baby", after the son of the former U.S. president cancelled a planned speaking tour.

The younger Trump, who had been booked on a three-day tour of Australia that was scheduled to begin in Sydney on Sunday, cancelled the trip on Wednesday, with organisers suggesting the reason was visa issues.

"It seems America isn't the only country that makes it difficult for the Trumps," the group Turning Point Australia, that describes itself as a non-profit in favour of "free markets and limited government", said in a Facebook post.

But O'Neil, one of the highest-ranking ministers in the centre-left Labor government led by Prime Minister Anthony Albanese, said Trump had been granted a visa, and poor ticket sales was the reason he called off his visit.

"Geez, Donald Trump Jr is a bit of sore loser," she said in a series of posts on Twitter that were later deleted.

"Donald Trump Jr has been given a visa to come to Australia. He didn't get cancelled. He's just a big baby, who isn't very popular.

It was not clear why the Twitter posts were deleted and O'Neil's office did not immediately respond to a request for comment.

Albanese also said the eldest son of former President Donald Trump had not been blocked from entering.

"Donald Trump Jr's visa was dealt with in the normal way. Like anyone else, he was entitled to come here. The deferral of his travel is a matter for him," he told reporters.

The younger Trump has long been a vociferous supporter of his father who is the front-runner in the 2024 Republican presidential nominating contest.