The government believes the leaderships of the UDA and UVF remain committed to the peace process and reform of their organisations, MPs have been told.
Secretary of State Theresa Villiers was updating the Commons on the security situation in Northern Ireland.
She said the latter half of 2013 saw persistent planning and targeting by terrorists culminating in a number of attacks before Christmas.
She said there were 30 "national security" attacks in NI in 2013.
More than half of these took place between October and December.
However, the threat level has remained the same as at the time of the last update in July 2013.
"The threat continues to be tackled and suppressed and there have been some significant successes by the security forces which should bring both immediate and longer term benefits," Ms Villiers said.
'Range of criminality'
Addressing loyalist paramilitaries, she said individuals associated with organisations continued to be involved in a range of criminal activity, including paramilitary assaults, organised crime such as drug dealing, and intimidation.
"Continued tensions within and between the two main loyalist paramilitary groups (UVF and UDA) also remain a cause for concern," she said.
"During 2013 we have witnessed loyalist-related public disorder including protests and security incidents that have taken place outside the offices of democratically elected representatives.
"There have also been attempts by paramilitaries to gain greater influence and control within loyalist communities."
However she said "we continue to assess that the collective leaderships of the UDA and UVF remain committed to the peace process and reform of their organisations".
Talking about dissident republicans, she said the group known as the 'new IRA' had continued to pose a significant threat and repeatedly "demonstrated its lethal intent".
"In the north west, the group has been responsible for a number of low level attacks as well as an attempted mortar attack on a PSNI station," she said.
"In Belfast they have claimed responsibility for the murder of Kevin Kearney, and conducted a shooting attack against police."
She said Óglaigh na hÉireann (ONH) was particularly active in the latter half of 2013, "demonstrating both its recklessness and its lethal intent with IED attacks against commercial premises in Belfast, and shooting attacks and IEDs against PSNI officers.
"The group has claimed responsibility for three particularly significant attacks: a vehicle borne IED which partially functioned close to Victoria Square shopping centre; a small IED which functioned in the Cathedral Quarter on a busy Friday evening; and an under-vehicle IED found under a former police officer's car by the officer and his daughter."
She said the Continuity IRA had continued to splinter into competing factions, several of which posed a localised threat to security forces.
"Many are more focused primarily on criminality than terrorism," she added.
Ms Villiers said high levels of cross-border police co-operation continued to be a crucial part of efforts to combat terrorism.
She said ways were being considered to further strengthen the co-operation.
"While we must remain vigilant about the threat from terrorism in Northern Ireland we must not allow it to overshadow the many positives to emerge from 2013, not least the successful hosting of both the G8 Summit and the World Police and Fire Games," the secretary of state said.
"That such high profile events passed without any significant security incidents taking place is a major achievement."