The INLA said it had disposed of its arms earlier this week
The legislation which enabled the international body set up to oversee the decommissioning of paramilitary weapons in NI has expired.
The Independent International Commission on Decommissioning (IICD) was established by the British and Irish governments in 1997.
On Monday, the INLA, the Official IRA and a breakaway faction of the UDA said they had disposed of their arms.
The IICD will not wind up its Dublin office until the end of the month.
The IICD's job was to facilitate disarmament among those groups that had renounced violence.
It will present its final report to the two governments later this year.
In total, the commission cost about £10m to maintain during its existence.
It was led by retired Canadian general, John de Chastelain. The other commissioners were General Tauno Nieminen from Finland and American general, Andrew D Sens.
The mainstream Provisional IRA decommissioned its weapons in 2005, while the disarmament of the main loyalist groups - the UDA and Ulster Volunteer Force - only came to pass within the last nine months.
John de Chastelain led the commission
The INLA, Official IRA and breakaway South East Antrim brigade of the UDA waited until the last day of the commission's mandate - 24 hours before an inter-connected amnesty from prosecution was due to expire - to announce they had given up their weapons.
Up until 9 February, paramilitaries moving weapons could use a certificate from the IICD saying they were moving arms from one cache to another to facilitate decommissioning.
Sir George Quigley, an independent witness called in to validate the IICD's engagement with the UDA, said the commissioners had proved what could be achieved through perseverance.
"A great element of the equation was simply their patience and willingness to talk and engage with people over long periods of time," he said.
"That has paid off. This was never going to be a quick fix overnight. They stuck at it and they got their rewards. In many ways they were rewarded for their endurance."
Senior trade union official Peter Bunting, who acted as a go-between when the INLA signalled it wanted to engage with the IICD, said despite the commissioners high ranking military background they had an "everyman quality".
"Trust was also very important," he said.
They held many discussions with these groups and through those they built up a degree of trust. It was vital that everyone bought in on the basis of trust."