A garda investigation - codenamed Operation Wireless - this week focused on the role of Triad gangs.
These well-organised Chinese gangs have taken over the cultivation of cannabis in sophisticated growhouses across the country.
But it is just one of the factions causing a serious headache for the gardai.
Garda Commissioner Martin Callinan yesterday lifted the lid on the inner workings of the criminal networks, revealing there are 25 major criminal gangs operating in the State.
The gangs have also forged links with international criminal networks -- extending their reach of drugs and weapons, according to Mr Callinan.
"Holland, Spain and the UK remain the key location for foreign liaisons, mainly due to established drug transportation routes," he told the joint Oireachtas Committee on Justice.
He also revealed how links between Irish and Russian organised crime groups -- who work together on drug and cigarette ventures -- continue to prosper.
However, what is of particular concern to gardai is the major foothold that Triad gangs have gained in the manufacture of cannabis.
This week alone over 4,200 cannabis plants with an estimated street value of €3.5m, were seized in searches.
The sheer brutality of Triad gangs was also laid bare during a terrifying incident at Capel Street last month when six gang members attacked two Chinese nationals in a cash dispute.
Knives, a hammer and a machete were among the weapons used in the attack on October 26. The victims were badly injured but were so terrified they refused to co-operate with the garda investigation.
A source said: "The culture of secrecy within these Chinese gangs is unbelievable.
"Apart from their sophisticated growhouses operation, these criminals are responsible for terrorising their own communities where they extort literally millions of euro every year from legitimate businesses."
The Triad code of secrecy extends to many of the other foreign criminals and their associates who are operating here.
In March, Lithuanian Nerijus Kelmelus (31) was injured in a gun attack in which fellow national Zilvinas Varnauskas and feared Tallaght drug dealer Andy Barry were murdered at Barry's home in Kilcock, Co Kildare.
Just weeks after the attack, gardai were forced to arrest Kelmelus -- who is not considered a criminal -- for withholding information about the double murder because he would not speak to them about what happened on the night -- despite seeing two of his pals brutally murdered.
When asked about the murders, Mr Kelmelus said: "I don't say anything. I don't care about no f***ing gardai. Go away or I get you."
While a number of Lithuanian criminals work as bodyguards or 'muscle' for Irish organised crime gangs, this year has seen a sharp rise in Polish gangs becoming more involved in the drugs trade.
"In the last few months, the Poles have become big players," said a source.
Gardai dismantled a major Polish gang in a special operation in west Dublin in May when they arrested six suspects and seized €1.6m worth of drugs, €20,000 in cash and two high powered cars. The operation also led to the seizure of 1,600 cannabis plants and seven kilos of herbal cannabis.
Highly sophisticated growhouses were discovered after detectives raided properties in the Blanchardstown area.
Investigations later established that the Polish gang had a money-laundering network including using a northside tanning salon as well as other prominent businesses to launder vast sums of cash they were making from their enterprise.
Some Eastern Europeans have also been involved in the production, dealing and widescale use of deadly drug crystal meth over the past 18 months.
Tablets such as Sudafed, which are normally taken to cure a common cold, have been used in labs here to make the addictive crystal meth.
Pharmacies in Dublin, Limerick and Kerry duly reported significant purchases of Sudafed in their premises and new regulations about its sale have been rolled out.
In August, a Polish man was arrested for questioning after gardai found a makeshift laboratory during a raid in Tralee, Co Kerry. Detectives also recovered crystal meth worth around €8,000 on the streets, and Sudafed tablets. A file is being prepared for the Director of Public Prosecutions.
Traditionally African gangs -- particularly Nigerian -- have been involved in the importation of cocaine into the country and the production of crack cocaine.
Apart from the illegal drugs trade, foreign criminals also control the bulk of organised prostitution in Ireland.
Last May, up to 10 mainly eastern European gangs -- who control brothels all across the island of Ireland -- were targeted in raids by gardai and the PSNI in which 140 vice dens were raided.
A Hungarian vice queen was arrested as part of that investigation which was part of Operation Quest -- the gardai's long- running investigation into prostitution.
Documents, cash, mobile phones and computers were seized in the operation, which involved specialist garda units such as the Criminal Assets Bureau, which took possession of the seized paperwork and computer files; and the Organised Crime Unit and the Garda Bureau of Fraud Investigation, which is involved in investigating international money-laundering operations.