Gerry Adams has written to the Taoiseach to ask him to intervene directly with the Egyptian Prime Minister over the case of Ibrahim Halawa.

Ibrahim Halawa is reported to be on hunger strike after being detained at a prison in Cairo, without trial, for 22 months.

Mr Adams was speaking at a meeting in Dublin this evening, which selected Mary Lou McDonald as the Sinn Féin candidate for Dublin Central at the next General Election.

The Sinn Féin leader said that it is imperative that the Irish Government exerts top-level pressure on Cairo to secure the Dublin teen's release.

“Ibrahim’s family feel the Irish Government’s approach to securing Ibrahim’s safety and freedom has been ineffective. They are not satisfied that the Government has acted to secure his release. They are naturally distraught and now increasingly concerned for his safety and welfare," Mr Adams said.

He also points out that Australian Prime Minister Tony Abbott appealed directly to Egyptian leaders to secure the release of journalist Peter Greste, who shared a prison cell with Mr Halawa. 

Ibrahim's situation was raised in the Dáil this afternoon by Sinn Féin's Mary Lou McDonald.

She says the diplomatic efforts by government have clearly failed, and affirmative action is now needed.

His family say they are increasingly concerned for his well-being, after his case was adjourned for a 7th time earlier this month.

According to the Irish Times, a letter from Ibrahim has been smuggled out of prison and says he will remain on hunger strike until he is allowed home.

He was detained during a protest in Cairo in August 2013 - an 8th court date for his trial has been set for August 2nd.

Ibrahim had been due to begin his studies at Trinity College when he was arrested in August of 2013 as he was attending a protest in the Egyptian capital.

Last month it emerged that Mr Halawa was not facing the same charges as some of the others within his group trial.