Ireland's data retention laws have been labelled 'extreme' by lawyers for convicted murderer Graham Dwyer at an EU hearing.

The European Court of Justice is today considering key legal aspects of the case.

The Former Architect was sentenced to life in prison in 2015, for the murder of Elaine O' Hara.

His conviction relied heavily on the retention of telephone data.

At the hearing in Luxembourg today, Dwyer’s lawyers are arguing that the data was obtained and kept illegally by the State during his trial.

The outcome of the hearing could have a bearing on his attempt to overturn his conviction.

Shane Phelan, Legal Affairs Editor at The Irish Independent, told Newstalk that both sides have been outlining their stance at the hearing in Luxembourg:

“On Graham Dwyer’s side his counsel Remy Farrell would have made points that in his view, Ireland’s data retention laws were extreme and provided very minimal protection against abuse,” he said.

“But on the side of the State, the arguments made by Attorney General Paul Gallagher were to the effect that if you did get rid of the data protection regime, this would allow serious criminal to put themselves beyond the reach of investigators.”

Dwyer won a High Court challenge to the validity of the law under which his phone data seized back in 2018.

The State subsequently appealed that ruling to the Supreme Court which referred six key legal questions on to the Court of Justice of the European Union (CJEU).

One of the questions the CJEU is being asked to consider is whether any finding that Ireland’s data access system was inconsistent with EU should be applied retrospectively.

Should it find that it should only apply from the date of the High Court ruling, Dwyer’s chances of mounting a successful will be dealt a significant blow.

A 15 judge Grand Chamber at the Court of Justice for the European Union is hearing the arguments today.

It is not expected to make a final decision until December or January at the earliest.