The family of an Irish man who has been detained in Iran since October is calling on the authorities here not to reopen an embassy in Tehran.
Bernard Phelan, who is originally from Clonmel in Co Tipperary, also holds French citizenship.
The Paris-based travel consultant was arrested while travelling and is being held in Mashhad in northeastern Iran.
The 64-year-old suffers from a heart condition and a chronic bone issue.
His family say he was recently sentenced to six-and-a-half years in jail for "providing information to an enemy country", a charge he denies.
His 97-year-old father Vincent is worried he will never see his only remaining son again. Bernard Phelan's brother Declan died 16 years ago.
The family held a press conference in Dublin, calling on the Government not to reopen the embassy in Iran.
His cousins, Patricia Phelan and Gregory O'Corry Crowe, said Mr Phelan has been held on "trumped up charges that he categorically denies" in Iran and his "health has been broken."
Earlier, Bernard's sister Caroline Masse also appealed to the Government not to reopen the embassy.
Speaking on RTÉ's Morning Ireland, she said: "We have appreciated all of the help that the Irish Government has given us, but they need to push this further. Bernard is ailing now and he's on death watch. Time is running out.
"They're potentially going to open an Irish embassy in Iran. We would say how can we normalise any communication with Iran while they have locked up an innocent Irish citizen in one of their prisons.
"We would encourage Ireland to shelve plans for any embassy until Bernard is released."
The Department of Foreign Affairs has said in a statement that the Government is extremely concerned about the case and that extensive engagement with the Iranian authorities is continuing.
Overall, Iran is holding at least 17 Western nationals, most of whom have dual nationality. They are described by their supporters as innocents used by Tehran as levers for negotiation.
