Bulgaria and Romania would likely join the euro zone in 2013-2014, the analytical unit of UniCredit Group said in its latest report titled The Euro goes Eastwards. It also warned that the main challenge to euro zone hopefuls was soaring inflation.

Once all aspirants from Central and Eastern Europe adopt the single European currency, the euro zone will expand by a third. Currently, the euro is in use by 320 million Europeans in 15 countries.

“The prospect for euro adoption is a main anchor for most of the countries from the 2004 and 2007 EU enlargement waves,” Debora Revoltella, UniCredit Group chief economist for Central and Eastern Europe, said.

“A main challenge presently is the inflation criterion because of the price pressure observed in almost the entire CEE region,” Revoltella added.

According to UniCredit Group, Slovakia stands 90 per cent chance to join the euro zone as of January 1 2009, as it got the greenlight for compliance with Maastricht criteria in the convergence reports from the European Central Bank and the European Commission.

Poland, Hungary and the Czech Republic, which are yet to set an official date for euro zone accession, are likely to adopt the euro in 2012-2013. For the three Baltic states, whose currencies are pegged to the euro, target euro zone accession in 2011-2012.