Polish euro referendum plan unwelcome in Brussels

"Firstly, Poland doesn't have a choice, when it comes to the euro. The adoption of the single currency is an obligation under the accession treaty," one EU official told the Polish newspaper, with Brussels declining to comment formally so far.

In the interview with Spain's El Mundo, Mr Kaczynski had said "It [euro entry] should be a subject submitted to a referendum, which would take place at the end of my legislature, which ends in 2010" adding "and I speak of the referendum, not of the introduction of the euro."

He added that ditching the Polish zloty would be "a limitation of the sovereignty [of Poland]" and stated that "the euro is still an experiment and it will be necessary to observe if it works well...its introduction can cause inflation and lower the standard of life."

Mr Kaczynski's ruling Law and Justice Party came to power last September, abandoning the previous government's plans to adopt the euro in 2010 but promising Brussels it will meet fiscal criteria to join the single currency by 2009.

The president - a moderate eurosceptic who distrusts free market economics - said the previous government had followed the commission's lead without being clear whether the single currency would be a success or not.

The liberal opposition party in Poland, Civic Platform, and the Polish central bank both want Warsaw to join the euro "as quickly as possible" in line with its original EU accession treaty commitments, however.

Poland's position is similar to Sweden's, which is also obliged to join the euro under its EU treaty, but which held a negative referendum on the subject in 2003 and has stayed out of the eurozone since joining the EU in 1995.

The UK and Denmark - which have also stayed out of the euro - negotiated opt-outs on the issue in their EU treaties, with the topic lost in the long grass politically-speaking in both countries.

Denmark's central bank governor Nils Bernstein said recently he expected his country to be sitting in the euro waiting room "for a very long time."

Slovenia will be the first of the ten new EU states to enter the euro zone in January next year, while Malta, Cyprus and Estonia are targeting January 2008.

Latvia is heading for 2009 entry while Lithuania saw its bid to join the euro rejected by the ECB and the European Commission earlier this year over minor inflation criteria infringements, with 2010 now held up as the new aim.