The gardaí were investigating an invoice redirection fraud
Two people have been arrested as part of an investigation into money laundering.
The men, aged 31 and 67, were arrested in Dublin on Tuesday morning morning.
They are both being detained under section 4 of the Criminal Justice Act at Blanchardstown garda station.
The arrests were part of an ongoing operation by the Money Laundering Investigation Unit at the Garda National Economic Crime Bureau.
The Investigation Unit was examining an invoice redirection fraud, where a European-based company was persuaded to send a VAT payment to the bank account of an individual instead of its actual recipient.
It is believed the database of the company, who were due to receive payment, had been the target of a malware attack.
This allowed the issuing of a request to change details of the real recipients bank accounts.
Once the funds were received, there were a number of onward transactions both within and outside this jurisdiction.
The gardaí say more than €900,000 was recovered before it could be dissipated.