Estonia, Lithuania and Slovenia, which joined the EU's Exchange Rate Mechanism (ERM-2) system on Sunday, are unlikely to adopt the euro before the start of 2007, the European Commission said on Monday.
The EU's executive said the eurozone normally expands at the start of a year, not in the middle, brushing aside speculation that the three EU newcomers could adopt the euro in mid-2006 - their earliest theoretical eurozone entry date.
"Usually the countries adopt the euro at the beginning of the year, not in the middle of the year," Commission spokesman Gerassimos Thomas told a daily news briefing.
Under EU rules, a member states wishing to join the eurozone must keep its currency for at least two years in the Exchange Rate Mechanism (ERM-2), in which the currency is allowed to trade within a narrow band around a parity rate.
The last country to join the eurozone was Greece, which adopted the euro on January 1, 2001 after spending almost three years in ERM-2.
Relatively small but economically stable Estonia, Lithuania and Slovenia are the first of 10, mostly central and east European countries that joined the EU on May 1 to have adopted the ERM-2.
Thomas reiterated that the countries must now push ahead with fiscal and structural reforms to meet other eurozone entry criteria, which involve exchange rate stability and limits on inflation, public debt, budget deficit and interest rates.
Cyprus, Latvia and Malta are expected to be the next EU newcomers to join the ERM-2, possibly in the beginning of 2005.
Bigger EU entrants with high budget deficits, such as Poland, Hungary and the Czech Republic, are expected to enter the eurozone at the end of the decade at the earliest.