Under the 2002 deal, Visa agreed to reduce levels of interchange fees for processing card transactions by the end of 2007 in return for immunity from antitrust action from the EU's Competition Commission.

But EU Competition Commissioner Neelie Kroes has told Reuters reporters that her staff will look again at the effect of Visa's non-negotiable interchange fees on competition when the card company's exption runs out at the end of this year.

The EC is already investigating fees charged by MasterCard for cross-border card transfers.

Last month Kroes delivered the findings of an inquiry into the European retail banking markets, initiated in 2005 following concerns that retail banks and credit card firms imposed artificially high interchange fees on retailers.

Despite repeatedly accusing retail banks and credit card companies of maintaining artificially high fees, the EC did not recommmend overhauling the controversial interchange fee structure.

Meanwhile in the the UK the Office of Fair Trading (OFT) is also investigating MasterCard and Visa's current UK interchange fee arrangements relating to consumer and commercial credit cards, charge cards and deferred debit cards.
The watchdog recently extended the investigation to include "immediate debit cards".