Two gangs in Dun Laoghaire are believed to have joined forces to target wealthy South Dublin areas.
The gangs, which are well known to gardai, commit dozens of burglaries and car thefts a month.
Areas which have been targeted by them recently include Dun Laoghaire, Stillorgan, Blackrock, Monkstown, Dalkey, Killiney, Sallynoggin, Cabinteely, Shankhill and Clonskeagh.
It's thought that children under the age of 16 sometimes carry out the crimes while more senior gang members plan them, The Journal reports.
Several South Dublin pubs have also been robbed in the past few months.