A Co Louth man, Mr Michael McKevitt, appeared in the Special Criminal Court in Dublin last night charged with directing an unlawful organisation.
He was also charged with membership of the "Real IRA".
Mr McKevitt (52) is married to Ms Bernadette Sands-McKevitt, sister of the IRA hunger-striker Bobby Sands and secretary of the dissident republican group, the 32-County Sovereignty Committee. He was remanded in custody.
The charge follows a Garda investigation into what it termed "paramilitary activity" in the Co Louth area. Mr McKevitt, a former painter and printshop-owner from Dundalk, is the first person to be charged in the State under the Offences against the State (Amendment) Bill, 1998, provision on "directing an unlawful organisation".
The offence, introduced in the wake of the Omagh bombing on August 15th, 1998, in which 29 people were killed, carries a maximum penalty of life imprisonment.
He is the second person to be charged under the Act with membership of the group calling itself the "Real IRA". The group also terms itself "Oglaigh na Eireann".
Mr McKevitt was arrested by gardai at his home in Blackrock, Co Louth, on Thursday at around 7 a.m. and taken to Balbriggan station where he was questioned by detectives. He appeared in court last night.
Three other people who were also arrested in Dundalk at the same time were released last night without charge.
All four were arrested under the Offences Against the State Act which allowed for their detention for up to three days without charge.
Last November a human rights group accused the media of a "campaign of vilification" against Mr McKevitt and his wife following the "Real IRA" bombing in Omagh on August 15th, 1998.
The report by British-Irish Watch has been sent to the UN Special Rapporteur on Freedom of Expression and Opinion.