Credit and debit cardholders will have to remember their personal identification numbers (PINs) from March 17th, 2007, or face being turned away at the till.

The Irish Payment Services Organisation (Ipso) has set St Patrick's Day as the date on which the PIN bypass option will be removed.

At the moment, forgetful shoppers can sign a receipt instead of entering their four-digit code into the keypad at the point of sale.

Some retailers have also not upgraded their systems and it is they, rather than the card issuers, who are currently liable in the event that transactions authenticated by signature turn out to be fraudulent.

"Although we have already seen a considerable reduction in the amount of counterfeit card, skimming and lost/stolen fraud cases, it is only when chip and PIN is being used correctly that we expect to fully combat the problem," said Úna Dillon, head of IPSO card services.

More than three million chip and PIN payment cards have been issued, according to IPSO.

"Ireland has invested over €100 million in the chip and PIN programme and IPSO is working together with banks, retailers and consumers to ensure the technology is used to its full capacity," Ms Dillon said.

IPSO will conduct an advertising campaign early next year to encourage consumers to remember their codes and remind retailers that they will have no comeback if they accept a fraudulent signature.

Holders of old-style chipless cards will continue to sign as usual after "PIN day" has passed.

The Europe-wide chip and PIN programme is designed to reduce incidences of certain types of fraud. However, it does not tackle relatively new kinds of fraud such as phishing, where consumers are duped into revealing their financial details, usually via an unsolicited e-mail linking to mock versions of financial institutions' websites.

IPSO is keen that a full transition to chip and PIN is completed sooner rather than later, so that Ireland doesn't acquire a reputation for being a soft touch on card fraud.