A new report says the IRA's ruling Army Council - which once directed its campaign of violence - is no longer operational.
The Independent Monitoring Commission has declared that the IRA has disbanded its terrorist structures and relinquished the leadership necessary to wage war.
The IMC report comes ahead of crucial talks between unionists and republicans aimed at securing the future of Northern Ireland's power-sharing government.
"We are aware of the questions posed about the public disbandment of (Provisional Irish Republican Army's) PIRA's leadership structures," the report said.
"We believe that PIRA has chosen another method of bringing what it describes as its armed struggle to a final close.
"Under PIRA's own rules the army council was the body that directed its military campaign.
"Now that that campaign is well and truly over, the army council by deliberate choice is no longer operational or functional.
"This situation has been brought about by a conscious decision to let it fall into disuse rather than through any other mechanism."
The report concluded: "The mechanism which they have chosen to bring the armed conflict to a complete end has been the standing down of the structures which engaged in the armed campaign and the conscious decision to allow the army council to fall into disuse.
"By taking these steps PIRA has completely relinquished the leadership and other structures appropriate to a time of armed conflict."
Secretary of State Shaun Woodward said: “This ground breaking report by the IMC makes clear that the Army Council is now redundant.
“As the Report states, 'the Army Council is no longer operational or functional'. By 'conscious decisions the standing down of the structures which engaged in the armed campaign... have allowed the Army Council to fall into disuse'.
“Crucially the IMC concludes that 'PIRA has completely relinquished the leadership and other structures appropriate to a time of armed conflict.'
“In their report the IMC state there are three key issues to consider.
“First that PIRA is both set on and will remain on a political path.
"Second, that as an organization PIRA is 'being allowed to wither away'.
"And third, whether PIRA 'might re-emerge as a terrrorist organization... our answer...is firmly in the negative'.
The Secretary of State added: “In the last few years we have seen huge progress in the political process. Today's report is a major event in this process.
"PIRA should now not just be judged by what it said it would do, but today by what the IMC tells us it has done.
“I urge people to read the report very carefully. As the IMC made clear 'what matters is that the armed conflict is completely over and the leadership structures have definitely ceased to function in the way they did during the time of conflict'.
“Today's Report confirms this has happened. The PIRA has met its commitment. It has abandoned all its terrorist structures, its recruitment and PIRA's so-called 'military' departments have ceased to function and have been disbanded.”