The new terrorist alliance, which is posing a major challenge to security forces on both sides of the border, has lured an experienced Provisional IRA bomb manufacturer out of retirement.
Anti-terrorist officers say the man's skills have given a major boost to the capacity of the New IRA alliance to mount mortar attacks.
He is being credited with the development of the mortars that were to have been used in an attack on a police station in Londonderry last month.
The attack was foiled by the PSNI after a tip-off from the gardai resulted in a van carrying four primed mortars being intercepted as it was being driven into the city. The Citroen Berlingo van had a Dublin registration plate but had not been stolen and gardai believe it was purchased in the capital in the weeks leading up to the planned attack.
The alliance had previously used a recently purchased car from Dublin in the murder of Northern Ireland prison officer David Black near Lurgan last October.
After the Provisional IRA ended its terror campaign, almost all of its top bomb makers faded into the shadows.
Several attempts were made by the dissident groups, the Real IRA and the Continuity IRA, to convince some of them to join their organisations.
But they remained in retirement until the formation of the New IRA last summer, merging members of the Real IRA, the Derry-based Republican Action Against Drugs -- mainly comprised of Provisionals -- and non-aligned groups operating in Belfast and east Tyrone.
Other former key Provisionals, including some based in Armagh, also joined the ranks and took control of the organisation, inflicting punishment on those they believed were holding on to some of the proceeds from "fund-raising" activities, which were meant to have been carried out on behalf of the dissidents.
Their involvement has been a major factor in attracting a handful of veteran bombers, who featured at the height of the violence in the Northern Ireland, back into terrorism despite the risks created by regular infiltration of dissident groups by the security forces.
The increased number of "old hands" joining the alliance has also been noted in intelligence gathering and monitoring by the PSNI and gardai.
Explosive experts say the quality of the mortars intended for use in Derry was on a par with those developed by the Provisionals during their campaign targeting then RUC stations and British Army bases.
The four mortars had been fully primed and "within minutes of being launched", with the most likely target reckoned to be the city's police headquarters at Strand Road.
Given the notorious inaccuracy of mortar strikes, the attack could have caused dozens of casualties in surrounding housing areas.
In February 1985, the RUC suffered its worst ever casualties in the Troubles when a 50lb mortar bomb landed inside Newry police station.
It killed nine officers and injured another 37.
Police now fear that the dissidents will use their improved mortars for a terror "spectacular" in the run-up to the G8 summit of world leaders in Enniskillen, Co Fermanagh.