Speaking at the Distillery Building conference in Dublin 7 on 5 April, he added that the quality, certainty and efficiency of legal services in London drove this work, but that Brexit was undermining this certainty.
Jurisprudence in Britain may diverge, post-Brexit, in competition law and state law, as well as in the enforcement of judgments, which would cause difficulties in running that legal business in a coherent way, the AG said.
The Irish and British legal systems have strong similarities in terms of commercial law, giving Ireland a head start on other jurisdictions competing for this business.
Quoting the Chief Justice Frank Clarke, the AG pointed out that Ireland would be a common law 'port' after Brexit.
Ireland benefits from stringent commercial case management in high-value disputes that delivers quick judgments, which makes it an attractive destination for such work, alongside excellent arbitration facilities.
He thanked both the Law Society and Bar Council for their joint initiative in promoting Ireland as a center of legal excellence (most recently in Washington DC at the St Patrick's Day festivities), which has been adopted as Government policy since January, with the IDA also supporting the project.
Ireland's legal infrastructure and political advantages were key to the success of attracting more business, he said.
Last month, Ireland became the second EU Member State, after Portugal, to sign a host-country agreement with the Hague-based Permanent Court of Arbitration (PCA), which is based on a 1907 convention for the settlement of international disputes.
The AG said that judicial co-operation would be a crucial issue, post-Brexit, for businesses that wanted to remain in the EU, and which needed certainty and stability.
Recognition and enforcement of judgments for those trading across borders is a fundamental need for international businesses entering into litigation, he said.
"I believe that Ireland has at least an equal, if not a unique environment [compared with other jurisdictions] for international disputes," he said.
Four big cases presided over by Ms Justice Caroline Costello in the High Court have hinged on an email or document produced through discovery.
The conference heard that the Civil Justice Review Group, chaired by Mr Justice Peter Kelly, is grappling with reform of discovery, as well as the need for more judges because of the increased volume of cases.
The Attorney General said that the Irish court system was already struggling to cope with the waste of time, and cost, that the discovery procedure involved, with too low a threshold for "relevant and necessary" documents.
"I've been in cases where one document was absolutely crucial," the AG revealed, despite often year-long delays between looking for documents and their production in court.
High Court Judge Caroline Costello said she feared a risk of real injustice in the absence of thorough discovery, despite the cost involved.
"It's been my experience, both as a practitioner and a judge, that at least four big cases turned on documents that were only produced by the party, dragged through the process, and by serious persistence on the part of the person who needed the documents .
"And they were casual emails which basically sank those cases, and that's why they were being kept from the court."
The conference was examining Ireland's future as a legal center of excellence for international dispute resolution post-Brexit.
Choice of forum
Regarding the choice of forum, Ken Murphy (Director General of the Law Society) pointed out that culture, in legal terms, went beyond language.
Discovery [or disclosure in EU terms] was a plaintiff-friendly device within the courts, he said, and this was an advantage that the common law system had that might send cases to Ireland, where a choice was available.
Murphy asked whether process and procedure might be an element of difference that could influence choice of forum, post-Brexit, and not just language and common law or civil law principles.
Advocate General Gerard Hogan (pictured) spoke from the perspective of the Court of Justice at the EU. He told Gazette.ie that there was an issue as to whether Ireland would remain a recognizably common law country in 20 years' time.
"The pressure for codification in large areas of private law - which are currently outside the influence and remit of EU law - I can see all of that changing," he said.
He warned that many Irish lawyers were not sufficiently familiar with matters such as the EU Unfair Contract Terms Directive.
Reach and influence
"Nobody could ever under-estimate the potential reach and influence of European law in so many areas," he said, citing his experience of seeing the CJEU at work over the last six months.
He advised everyone involved in contract law or banking law to examine the directive and study it in terms of case law.
Judges in the Netherlands, France and Germany were being trained in the common law as they competed for this business, the conference heard.
Advocate General Hogan said that the magnitude of change, post-Brexit, to the fabric and structure of our legal system would be very significant.
"We can only intellectually imagine it, but it won't feel real until it happens," he said.
Despite the British and Irish legal systems going their own ways in many respects over the last 100 years, both are joined umbilically in key areas of private law.
Deny our heritage
It would be foolish to deny our heritage in this, he said, despite what legal nationalists might feel.
The Advocate General said that the “mothership” would be finally untethered, post-Brexit, and that might not be a comfortable place to be, as we were prised away from our common law heritage.
We would move towards the corpus of CJEU jurisprudence in a range of areas, from family law to European Arrest Warrants, to copyright, which we will have to apply but English courts won’t.
“The pressures will be very significant for us to be part of a homogenous, civil-law-inspired system of private law,” he warned, adding that these pressures would be impossible to withstand.
Attorney General Seamus Woulfe disagreed, however, and wondered whether British judges would disengage from EU laws after 45 years.
"The fear of isolation will lead them to be inclined to EU law, indirectly continuing for a while," the AG said, questioning whether Brexit would ever actually happen.
"I can say honestly that our standing has never been higher [in Europe]," Advocate General Hogan said, revealing that he heard constant heartfelt praise for the quality of Irish references, with judgments from our national courts circulated to every member of the CJEU .
Ireland had exactly the right measure of article 267 references, he believed, whereby national courts could put questions to the CJEU.
"It is that type of soft power that helps us in the standing of our legal system," he said. This would seep through European consciousness, which could only help the goal of establishing Ireland as a center of legal excellence.
The strength of the Irish tradition of oral argument also bolstered the reputation of Irish law, he concluded.