Technical components used to trigger massive bombs have been found among a hidden arsenal belonging to republican dissidents, it has emerged.

Time Power Unit (TPU) circuit boards deployed in the past by the Provisional IRA to detonate large explosive devices were discovered during a garda search operation over the weekend in the south-west of the Irish Republic.

The gardaí seized guns and several hundred rounds of ammunition in a planned search of Glenagross Wood, in Meelick, County Clare.

Explosives, the TPU components and documentation were also discovered during the operation to disrupt the activities of armed republicans still opposed to the ceasefire and the power-sharing settlement in Northern Ireland.

The seizure of the TPU units is particularly significant given the role of this technology in previous bombing campaigns both in Northern Ireland and in Britain during the 1980s and 1990s. The ability of gardaí to go directly to the hidden weapons haul also indicates the level of intelligence the force is receiving from within the various dissident republican factions who, particularly in the Irish Republic, appear to have been heavily infiltrated by agents.

A spokesman for the Garda Síochána said the firearms and explosives had been taken away for examination but that no arrests had been made during the operation.

Jeffrey Donaldson, the Democratic Unionist MP for Lagan Valley, pointed out that this was just the latest blow to dissident republicans by the Garda Síochána.

Praising the Republic's police force, the DUP MP said: "We must give credit to the garda who have had a number of successes recently in disrupting and in apprehending weapons caches. This undoubtedly helps to save life in Northern Ireland and is an indication of the level of co-operation between the two police services and this is something to be welcomed."

During the summer the garda uncovered the largest ever dissident republican arsenal buried on land at the Old Airport Road in north Dublin. It included explosives and guns that the Provisional IRA should have decommissioned years earlier.

The haul in July included 15kg of semtex explosive that the late Libyan dictator Muammar Gaddafi had supplied in the 1980s. The buried weaponry also included handguns, shotguns, an Uzi submachine gun, electronic devices to disrupt mobile phones and more than 1,300 rounds of ammunition.