Kylie Moore-Gilbert has been in jail in Iran since attending a conference there in 2018.
She was reportedly freed on Wednesday morning, pictures from the TV station IRIB appear to show.
The footage apparently shows her released from prison and looking well.
State media suggested she had been exchanged in return for the release of three Iranian men who had been detained abroad.
Before her incarceration, Moore-Gilbert, who studied at Cambridge, had been a Middle East scholar at the University of Melbourne.
She was convicted following a secret trial and sentenced to 10 years in jail in 2018.
Her release will raise hopes for the fate of Nazanin Zaghari-Ratcliffe, a dual UK-Iranian national who has been held in Iran since 2016.
Kate Allen, the director of Amnesty International UK, said: “We were always extremely concerned that Kylie was imprisoned solely for exercising her right to freedom of expression — including through her work as an academic — and it’s an enormous relief to hear of her release.
“There may now be renewed grounds for hoping that UK-Iranian dual nationals like Nazanin Zaghari-Ratcliffe and Anoosheh Ashoori will also be released from their unjust jail terms in Iran in the coming days or weeks.”
Ms Zaghari-Ratcliffe’s husband, Richard, told the PA news agency: “I don't know what it means for us, it's definitely a good thing for Kylie and it's definitely a good thing for all of us that deals are being done.”
“All I can see on our case is either no news or bad news, but that was also true in Kylie's case, we either only saw bad news until this afternoon and it was two years of horrendous cruelty in a terrible situation and great dignity from her and her family,” Mr Ratcliffe said.
“Now it looks like it's over and she can begin to heal, they can begin to heal.
“It can happen, and I think it's important. She shows there's light at the end of the tunnel and that's a really good reminder for me and for Nazanin when feeling really glum.”
He added: “Realistically, people come home. We could come home soon. Not to say we will, but we could.”
Before her apparent release, Ms Moore-Gilbert had gone on hunger strikes and pleaded for the Australian government to do more to help free her.
She had also written letters to the Australian prime minister warning that she had been subjected to "grievous violations" of her rights, including psychological torture and solitary confinement.