The sisters of Dubliner Ibrahim Halawa say he told judges in Egypt today that he is innocent and asked to be allowed to return home.
It came as his trial was delayed for a 17th time on his 21st birthday.
Mr Halawa was 17 when he was arrested in a mosque in 2013 during protests against the ousting of then president Mohamed Morsi.
Amnesty International has called for him to be released immediately and says he is a prisoner of conscience.
Executive Director Colm O'Gorman said his ongoing detention represents an inexcusable violation of both international and Egyptian law.
In a statement, Minister for Foreign Affairs Charlie Flanagan said the Government's focus is on applying maximum pressure on Egyptian authorities in support of an application for Mr Halawa’s deportation to Ireland.
The Government has also requested that he be considered for release under a new Egyptian government amnesty scheme for young prisoners.
Mr Halawa's trial is expected to reconvene again on 17 January.