Interoperability standards are at the heart of a new antitrust probe launched by the European Commission into the online payments market.

Competition Commissioner Joaquín Almunia said that the investigation will examine whether big players in Europe's banking sector are blocking other companies from entering the e-payments market.

The European Payments Council (EPC) is currently developing a standard framework for e-payments called the Single Euro Payments Area (SEPA) that will allow internet users to buy online regardless where they are located in Europe, and to pay the merchant using their own internet banking services and their current bank account. Under existing systems, users can have payments debited from their accounts but only within national borders.

But the Commission has received a complaint alleging that the standardization process is locking out non-bank payment providers such as Paypal and Hipay.

EPC members include Deutsche Bank, HSBC, BNP, Santander and Barclays, and the Commission is concerned that if new, non-EPC players are blocked from entering the market, consumers could end up forking out more for online transactions.

The Commission said it intends to investigate whether the e-payments standardization process will not unduly restrict competition, for example through the exclusion of new entrants and payment providers who are not linked to a bank.