Security forces on both sides of the border have had considerable success in frustrating the activities of the armed groups.
But while they are small in comparison with paramilitary organisations operating at the height of the Troubles, observers have often warned of the danger they pose.
* Óglaigh na hÉireann In the past it has been described as a small organisation, but it has become one of the most dangerous.
The Independent Monitoring Commission previously said the group was intent on violence and was engaged in other criminal activities.
It is said to include former members of the Provisional IRA and has worked closely with the Real IRA.
In January 2010 it claimed responsibility for an under-car bomb that left Catholic police officer Peadar Heffron fighting for survival. An Irish-language specialist and a prominent member of the PSNI gaelic football team, he narrowly escaped with his life, but suffered major injuries.
* Continuity IRA: It emerged in the wake of the splits in the republican movement of the 1980s.
Sinn Féin voted to overturn its long-standing ban on taking seats in the Dáil. The move in 1986 saw objectors breakaway to form Republican Sinn Féin.
The splinter party denies links to the Continuity IRA that emerged later, but the pair are widely seen as being connected.
The Continuity group launched its first major attacks in the mid-1990s. At that time the mainstream republican movement announced a ceasefire and began to move towards a purely political path.
The group is said to be most active in border areas of Northern Ireland.
In March 2009 the Continuity IRA shot dead PSNI Constable Stephen Carroll in Craigavon, Co Armagh.
* The Real IRA: The dissident group is infamous for its bombing of the Tyrone town of Omagh in 1998 which killed 29 people.
The Real IRA was formed in the late 1990s when senior Provisional IRA members split from the main organisation.
It is the largest of the dissident groups, but observers have said it has worked with both the Continuity IRA and Oglaigh na hÉireann.
It shot dead two soldiers outside Massereene army base in Co Antrim in 2009, and has been linked to a string of bomb attacks.
* Republican Action Against Drugs: The dissident group has been linked to so-called punishment shootings and blamed for attacks in the Derry area.
But it has been suggested the name may be a cover for other paramilitaries.