Garda and military intelligence have kept republican political group Saoradh under surveillance since its creation three years ago.
The organisation - which has close links to the New IRA - was widely condemned after it marched through the capital as part of an Easter 1916 commemoration.
The march went ahead less than 48 hours after the murder of Lyra McKee.
The journalist died after a gunman - believed to be linked to the New IRA - opened fire on a crowd of PSNI officers, journalists and onlookers in the Creggan area.
A similar Easter commemoration planned for Derry yesterday was cancelled on Friday.
Since its creation in September 2016, Saoradh has been described as the New IRA's political wing.
These links became evident when forty-four-year-old Kevin Braney, the so-called leader of the New IRA, was arrested for IRA membership.
At the time of his arrest, he was chairperson of Saoradh Dublin.
He was convicted of IRA membership in 2018 and earlier this year was given a life sentence by the non-jury Special Criminal Court for his role in the murder of Peter Butterly.
Braney had been a long-term target of the Special Detective Unit (SDU) and was charged on two previous occasions for alleged IRA membership, but was acquitted both times.
He was a founding member of Saoradh Dublin in September 2016, and served as its chairperson until his arrest in August 2017.
Braney has been held in the maximum security Portlaoise Prison ever since.
Sources say that as a result of the evident ties between Saoradh and the New IRA, Irish security agencies have kept "a close eye" on the political party.
"Both groups are brought up together in regular high-level State security assessments," said a senior source. "The belief is that they are inextricably linked."
The New IRA was formed in 2012 from an alliance of former factions of the Real IRA, the Derry-based Republican Action Against Drugs (DRAAD) and republicans elsewhere who had remained largely unaligned because of infiltration of existing dissident groups by gardai and the PSNI.
The group, which has about 50 activists and 200 logistical supporters operating on this side of the Border, has a stronghold in Derry as well as Dublin.