Amnesty International is gravely concerned for the welfare of an 83 year old Australian citizen, Shokrollah Jebeli, who has been jailed in Iran for two years.
The dual Australian-Iranian citizen was detained in January 2020 over a financial dispute with an Iranian intelligence official.
"We have written to the Australian and Iranian authorities urging that Mr Jebeli is released immediately on account of his poor health and the conditions in which he is being held," Amnesty International Australia's campaigner Nikita White said.
"Shokrollah, our father and grandfather, has been in Evin prison, two years to the day", a family spokesman said according to the human rights group.
"He has survived 730 days in miserable conditions, an innocent man...Every day spent in that prison is like a year for Shokrollah"
Mr Jebeli's family said he suffered a stroke in the notorious jail's horrific conditions and that his detention has taken a toll on him psychologically.
"This is our cry for help on behalf of Shokrollah, to the people of Australia, to the Australian government and to all who value human rights, justice and stand for human decency"
"We cannot do this alone, we need your help. Please help this family save our dad and our grandad", the family said.
Foreign Minister Marise Payne previously said Iran did not recognise dual nationalities and was refusing Australia's attempts to provide consular assistance.
She said Canberra was constantly pressing Iranian authorities for consular access and seeking to ensure Mr Jebeli received the medical care required.
British-Australian academic Kylie Moore-Gilbert was imprisoned for two years in the same Iranian jail on spying charges, which she always denied.
She returned to Australia in November 2020 after a sustained global campaign demanding her release.