Telecoms operators such as BT and Internet service providers such as Google, Microsoft’s and Hotmail, should also be included, the foreign ministry said in a written response to questions.

The US is pressuring the European Union and SWIFT to expel Iranian banks from the network to deprive Tehran of funds.

The US seeks tougher scrutiny of banking transactions and oil shipment financing with Iran, which it accuses of seeking to develop nuclear weapons.

Belgium’s foreign ministry said: “If such a measure is decided, it has to apply to all actors, including telecom and other companies providing such services (Google, Yahoo, Hotmail, BT, SIA, etc).”

“It is regrettable that one company is singled out, especially given its valuable contribution to the stability of the international financial system.”

SWIFT, whose headquarters are just outside Belgian capital Brussels, is vital to international money flows, exchanging an average 18 million payment messages per day between banks and other financial institutions in 210 countries.

Faced with outside pressure, SWIFT’s typical response has been to point out that it does not cary out transactions and is only a messaging system, more akin to a telephone service and that member banks are responsible for the content of messages.

Earlier this month, SWIFT said it was working with US and EU authorities to resolve the issue.