Former minister for finance Dermot Ahern said tiger kidnappers could have stolen €300 million in one raid in Ireland a number of years ago.
Mr Ahern recalled how a bank official was forced to go into a Dublin city centre branch and access the vaults while his family was held hostage at his home.
He was given two holdalls by the gang and told to fill them with cash.
Mr Ahern said the gang did not know the official in question not only had access to €7 million he handed over to them, he had access to €300 million in the bank’s vaults.
In his Daily Mail column, Mr Ahern said the official could have taken all of it, except he did not have enough arms to carry it.
The former minister said Ireland had been plagued with so-called tiger kidnappings between 2008 and 2011.
During a tiger kidnapping, gang members take a bank official and their family hostage and force the official to then go to the bank and take cash from it.
Mr Ahern did not reveal when or where the incident took place. In 2009 more than €7 million was taken from the Bank of Ireland in College Green by an official during a tiger kidnapping.
Following that raid, Mr Ahern told the Dáil he had contacted bank chief executives and they introduced new protocols but he declined at the time to disclose what those protocols were.
In his column, Mr Ahern said he was “astounded” to learn at the time meeting with bank officials that they did not use tracking devices to monitor money.
As a consequence, at-risk bank officials were told what wads of notes had a tracking device.
Mr Ahern added: “The criminal gangs quickly realised that the banks were using such devices and the level of tiger kidnappings and ATM raids consequently dropped significantly.”
However, he pointed out criminals would divert their attention to easier targets and credit unions and post offices would be targeted instead.
He referenced the jailing of a gang leader, Paschal Kelly (53) as a case in point. Kelly was jailed for 18 years for a €92,000 post office robbery during which three women were tied up and abducted.
Susan Lawlor , her daughter Emma and an Italian student Gabriella Saisa were tied up before the robbery took place at Bayside Post Office.
Mr Ahern said Ireland was moving to a cashless society but said that raid, and on one of ATM in Co Monaghan before Christmas, showed there was still plenty of cash about.