Donald Trump Jr was scheduled to speak in Sydney, Melbourne and Brisbane between July 9 and 11 as part of a "Trump Live" tour.

But on Wednesday the organisers, Turning Point Australia, said in a statement they had been forced to postpone the tour due to the visa delay.

"The visa, which has now been issued, was only received late afternoon of Wednesday 5th July, only 24 hours before Donald Trump Jr was set to board a flight to Sydney," the statement said.

The organisers said 8000 tickets had already been sold across the three states, with all VIP tickets priced as a high as $2500 selling out in the first week of the tour announcement.

"Ticket holders are urged to hold on to their tickets, with details of the rescheduled date to be confirmed in the coming days," Turning Point Australia said in a post to the tour website.

The website said Trump Jr's "fearlessly outspoken, anti-politically correct stance has captured the imagination of conservatives from around the world".

South Australian Liberal Senator Alex Antic, who was set to MC the speaking tour, was quoted in the tour organisers' statement saying he was disappointed but not surprised by the tour postponement.

"I'm looking forward to the show getting new dates. Aussies want to hear from conservative warriors like these guys," he said.

A spokesman for Home Affairs Minister Clare O'Neil told Nine newspapers there was no immigration impediment to Trump Jr coming to Australia.

Australian Associated Press