Taoiseach Enda Kenny has written a letter to Egyptian President Abdel Fattah el-Sisi pleading for the release of a jailed Irishman on humanitarian grounds.
Ibrahim Halawa, 21, has been incarcerated without trial for almost four years after being detained during Muslim Brotherhood protests in Cairo in 2013.
In recent weeks he has been refusing food while suffering a heart complaint and skin disease.
Mr Kenny revealed an Irish GP travelled to Wadi al Natrum prison last week along with ambassador Damien Cole and met with Mr Halawa for an hour-and-a-half.
He sat in on a medical examination carried out by an Egyptian doctor and has written a report on his observations, which is expected to be given to the Halawa family in the coming days.
Mr Kenny said the GP recommended Mr Halawa's release on humanitarian grounds and for him to be flown back to Ireland to undergo further specialist tests.
The Taoiseach revealed the detail of his plea to President el-Sisi after being pressured in the Dáil on the Government's response to the long-running case.
"We are very concerned about it and it is receiving the most urgent attention of any Irish citizen abroad," he said.
Mr Halawa, the son of a prominent Muslim cleric in Dublin, Sheikh Hussein Halawa, was imprisoned after being detained in a mosque near Ramses Square in Cairo as the Muslim Brotherhood protested over the removal of elected president Mohamed Morsi in August 2013.
He has been in jail for more than 1,300 days awaiting a mass trial along with hundreds of others.
The case is due before a court again on Wednesday.
During his time in jail his family have reported that he has been tortured, suffered electric shocks and beatings, been spat on and moved without their knowledge.
His sister Somaia revealed he collapsed on Sunday and was rushed to the clinic in Wadi al Natrum prison after his blood sugar level plummeted but he refused glucose treatment after regaining consciousness.
He was also said to be suffering dehydration and vomiting.
Another sister, Khadija, said she did not recognise her brother when she went to visit him last week for the first time in three months.
President el-Sisi has given previous assurances that Mr Halawa will be freed but only once his trial is over.