Iran has released Australian-British academic Dr Kylie Moore-Gilbert, who was serving a 10-year prison sentence for spying, in exchange for three Iranians held abroad.
"I am extremely pleased and relieved to advise that Dr Kylie Moore-Gilbert has been released from detention in Iran and will soon be reunited with her family," Australian Foreign Minister Marise Payne said.
"The Australian government has consistently rejected the grounds on which the Iranian government arrested, detained and convicted Dr Moore-Gilbert. We continue to do so."
The Free Kylie Moore-Gilbert campaign group said it was "a very bright day" in Australia after the release.
"But let’s be clear: this should never have happened," the group said.
"Kylie was held to ransom by the Iranian regime, which saw fit to take an innocent Australian woman hostage in order to bring its own convicted prisoners abroad home.
"It’s a despicable business model with incalculable human consequences.
"We'd like to pay our respects to the other foreign nationals who remain imprisoned in Iran today under the same nefarious circumstances and call on their governments to do everything necessary to bring them home.
"Lives are being needlessly destroyed by a morally bankrupt regime that knows no currency other than cruelty."
State media corporation Irib in Tehran first reported the swap saying an Iranian businessman and two other nationals had been freed.
It provided no further information on the exchange.
Irib aired footage without commentary showing three men being met by officials, and images of Dr Moore-Gilbert in a green van.
The arrest of the Islamic Studies lecturer at the University of Melbourne was confirmed by Iran in September 2019 but it is believed she had been detained a year earlier.
She denied the charges of spying for Israel and supporters said the allegations were trumped up.
According to her letters that were smuggled out of prison and published in British media in January, Dr Moore-Gilbert rejected Tehran's offer to work as a spy.
She wrote that the first 10 months in an isolated wing of Tehran's Evin Prison, run by the Islamic Revolutionary Guard Corps, had "gravely damaged" her mental health.