Dublin: Police recovered millions in stolen cash and were interrogating seven suspected robbers on Saturday, a day after a gang took a bank employee's family hostage and forced him to rob his own branch.

Police said that shortly before midnight they raided two houses in the inner north Dublin district of Phibsborough and further west in Blanchardstown, where they recovered at least a third of the stolen money.

Six men and a woman were arrested and were being interrogated separately at Dublin police stations, where they can be held for up to 72 hours before being charged or released.

The big operation, organised by assistant commissioners Dermot Jennings and Al McHugh, was launched within hours of the heist from the Bank of Ireland branch at College Green in the centre of Dublin.

On Friday, six armed, masked men stormed into the rural home of Bank of Ireland worker Shane Travers. They tied up his partner, her 5-year-old son and her mother and told Travers they'd be killed unless he cooperated.

Such hostage-taking tactics are common in Ireland's criminal underworld - but never in Republic of Ireland history have they netted anything close to the $7 million (Dh25.69 million) that Travers carried out from his branch on Friday morning.

His family had been abandoned inside a van north of Dublin, but escaped on their own and were not seriously harmed.

Initially, Justice Minister Dermot Ahern and police chiefs offered veiled criticism of Travers' apparent failure to notify police until after he had handed over the mountain of cash. That violated police and bank instructions on how to handle a bank heist involving hostage-taking.

"It is a fact that police didn't know about this incident until the money had actually left the bank premises," Ahern said.

"Under normal protocol that shouldn't be the case, because the sooner they know about it, the sooner they can put in the necessary checkpoints, etc."

So-called "tiger kidnappings" - when gangs seize families of bank officials and force them to breach their employers' security - are common crimes in Ireland, a close-knit society where criminals can closely track their targets. But they typically involve thefts below $1 million.

Friday's raid on the Bank of Ireland branch in College Green, the tourist heart of Dublin, represented by far the biggest robbery in the history of the Republic of Ireland. But it pales in comparison with a £26 million (Dh140.4 million) 2004 raid in the neighbouring British territory of Northern Ireland.