The gang, led by a notorious criminal, numbers around 15 people and centres around an extended family.

Garda sources said it has been operating for around 20 years and involves generations of the same family.

“This gang is one of the most prominent travelling criminal gangs in the country,” said a Garda source.

In yesterday’s operation, led by gardaí from the south east region, more than 80 members took part in nine co-ordinated searches.

It included a number of specialist national agencies, including the Criminal Assets Bureau and Revenue.

In a statement, a Garda spokesman said that the search operation was the result of an intelligence-led investigation in the Waterford and Wexford Divisions.

The spokesman said gardaí were “targeting an organised criminal gang operating nationally and in the south eastern region”.

“The operation has over 80 gardaí taking part in a total of nine co-ordinated searches with the assistance of the Criminal Assets Bureau and the Drugs and Organised Crime Bureau, Stolen Motor Vehicle Investigation Unit, Garda Air Support, and officers from Revenue Custom and Excise,” said the spokesman.

He added that property, believed to have been stolen, worth in the region of €75,000 was recovered and two arrests were made.

It emerged that the gang is considered to be one of the country’s seven biggest travelling gangs.

“This gang systematically targets two or three places in a country and returns home,” said a garda source.

“These are professional thieves who are gainfully employed travelling the length and breadth of the country, robbing old people, jewellers, committing burglaries, and amassing a fortune.”

He said the gang is led by an individual involved in crime for some 20 years and comprises an extended family, involving sons, wives and nephews, who are from the Travelling community.

Gardaí number the gang as having about 15 members, as well as “hangers-on”.

The source said these gangs were “becoming more and more forensically aware” and that it was “very difficult to catch them”.

This operation is part of a hit list drawn up by CAB, focusing on these seven gangs.

In addition to the gang hit yesterday, they include three gangs in west Dublin, an international gang based in Limerick, as well as a gang in Galway and the Midlands.

CAB boss, Detective Chief Superintendent Eugene Corcoran, told the Irish Examiner in January that the activities of these gangs had become a “particular menace” and a primary focus for Garda operations.