Modern office blocks could be declared 1916 monuments following a ruling in the Moore St case, the Government has claimed.

Michael McDowell SC for the attorney general was speaking at the start of an appeal against a High Court ruling that extended national monument protection over a larger "battlefield site" around Moore St.

Mr McDowell said that some buildings on Moore Street which were constructed after 1916 are now national monuments.

Similarly, houses along Northumberland Rd and the Clanwilliam office building could also be declared national monuments as they were in vicinity of fighting on Mount Strteet bridge during the 1916 Rising, he said.

Mr McDowell said the High Court action by Colm Moore and the 1916 Relatives Association "was a bridge too far for judicial review".

He also said Mr Moore had failed to challenge previous rulings in the case.

These included the then Minister for Heritage declaring Numbers 14-17 Moore St a national monument in January 2007 and An Bord Pleanála granting planning permission for the Dublin Central shopping centre development on the site in March 2010.

Mr McDowell said the usual three month time limit for a judicial review had been "blithely ignored".

The judicial review was based on a letter written to the then Minister for Culture, Heritage and the Gaeltacht Heather Humphreys in 2015 asking that statutory powers be used to revoke the previous national monument designation he said.

But the issue was academic as she had already made up her mind and given consent to the construction of an interpretative centre.

To revoke her decision would mean previous consents given by the minister would be "bulldozed out of the way", he said.

Mr McDowell said this would also mean "immunising the land" and depriving huge property rights for the owners.

The refusal by Ms Humphreys to revoke her decision was the basis for the judicial review.

But Mr McDowell said the action was "most unwarranted" and that the High Court is not entitled to declare a national monument.