DATA protection officers visited a Dublin nightclub following concerns over 'finger-scanning' equipment used to keep tabs on customers.

But the venue manager, who first introduced the technology to Ireland, has insisted it is not a biometric data recorder and cannot differentiate between customers.

The machines – which can tell whether or not a customer has already been inside the nightclub – are simply used as a welcome substitute to the traditional 'ink stamp'.

Following an inspection of the machines, they were given the all-clear, said Philip Roe of Tamango night club in Portmarnock, north Dublin.

"Someone rang them up – a customer who was obviously concerned about it – and the Data Protection Office got in touch with us," he said.

"They wanted to come out and have a look at it but they said it was absolutely fine because it doesn't hold any information."

The machines are called 'Smokescreen' as they were initially designed to allow people in and out of a premises following the introduction of the UK's smoking ban but have now been welcomed as a means to avoid ink stamps on patrons' hands.

Following their success at Tamango, they were also introduced by two other Dublin venues – Krystle on Harcourt Street and Parker Browns in Dundrum – both eager to find an efficient monitoring system that negates the need for hand stamps.

"You put your finger on the scanner and it looks for four or five different points on your finger and it converts this to a code. It doesn't store any fingerprints," explained Rowe.

"People had been getting ink stamps on their hands and then we were using a UV scanner which was rubbing off so I eventually came across the bio-scan. At the end of the night you just reset the machine for the next night."

The system has been welcomed, not only as an accurate means to allow customers in and out of certain areas of clubs, but also as a way to prevent customers cheating the stamp system and entering for free.