Egypt has deported one of the three Al Jazeera journalists who have been held in custody for more than 400 days.

Australian reporter Peter Greste was deported yesterday following a decree from the Egyptian government that foreign detainees can serve out their sentence in their home country.

So what could this mean for Irish detainee Ibrahim Halawa, who is a week away from retrial in an Egyptian court?

The Dublin-born teenager was arrested at Cairo’s Al-Fath mosque in August 2013 following protests against the ousting of former Egyptian President Mohammed Morsi. The 19-year-old has been detained for almost 18 months.

Halawa is charged with murder, attempted murder and destruction of public property during an attack on a police station. He is charged along with another 193 defendants.

His hearing was postponed at the beginning of the month for the third time. His family have warned the delay could deepen depression which he has suffered in recent weeks.

Newstalk Breakfast spoke to his sister Nusayba this morning who is in Egypt ahead of his trial.

She says Greste's release has been a welcome development.

"After I heard that went to Peter at 7 o'clock in the morning and they just took him out, even without him even knowing, I...hope that in the morning I see my brother knocking on the door and he would be like 'Oh, I hot released'" she said.

"Of course I have hope, that's what keeps us going on".

"To have hope that maybe he would be released tomorrow, maybe after tomorrow, maybe now" she added.

You can listen to her full interview here: