Security sources say that the weapons -- mainly pistols and revolvers -- have been linked to the IRS via ballistic testing and documentation.
Some of the weapons have been traced to pre-ceasefire attacks while others have been matched by their serial numbers to the inventory of guns and ammunition supplied by the Libyan government to the British Foreign Office.
The discoveries -- which the PSNI refuses to discuss -- support the RUC Special Branch estimation that around 60 per cent of all IRA weapons were decommissioned five years ago.
The Special Branch took into account the permanent loss of IRA weapons which were buried and could not physically be retrieved, the theft of weapons by the former quartermaster general of the organisation Michael McKevitt, and the intention of the IRA to hold on to new weapons not on the Libyan inventory.
In September 2005, the IRA decommissioned a substantial quantity of handguns, rifles and heavier calibre weapons and explosives under the supervision of General John de Chastelain.
However, many guns and a quantity of explosives had already been taken from IRA bunkers by the REal IRA leader.
Now guns being seized by the PSNI in searches are being linked to weapons supplied by Colonel Gadaffi and used before the 1994 ceasefire.
Other guns have been linked to the Libyan shipments through their serial numbers which can be traced to batch numbers supplied by Libya. Ammunition in the chambers has also yielded links to corresponding batch numbers, one PSNI source revealed.
Since April 2008 more than 170 unregistered guns have been seized by the PSNI across Northern Ireland.
From April of last year up to the end of February, 62 guns were seized.