The 2009 target for converting Poland to the Euro may have to be delayed, as some Polish leaders have raised doubts about its feasibility.
Polish Prime Minister Jaroslaw Kaczynski said today that euro adoption could be risky for central Europe's biggest economy for another few years, but that real convergence was progressing fast.
The government plans to meet euro entry requirements in 2009, but so far has not set a date when the zloty could be withdrawn in favour of the Eurozone currency.
The coalition government, led by Mr Kaczynski's Law and Justice party, has been seen as eurosceptic since it was formed after general elections in 2005.
Finance Minister Zyta Gilowska and central bank Governor Slawomir Skrzypek have already said Poland may not adopt the euro until 2012 at the earliest.
'In our accession treaty, there is an obligation to join the common currency area,' Mr Kaczynski said.
He added: 'For as long as the value of the zloty and its purchasing power is this different as it is now, this experiment would be incredibly risky - economically and socially.'
Also today, the prime minister said Poland is ready to drop its opposition to the EU's new voting system at a summit this week if it wins provisions giving it a strong voice in the bloc.
He said Poland was ready for a compromise because the EU's drive to replace the defunct constitution with a slimmed-down treaty to improve its functioning seemed unstoppable.
Mr Kaczynski and his twin brother, Polish president Lech Kaczynski, threatened to block treaty talks because Poland would lose most from the proposed new voting system.
Poland wants to replace the double majority decision-making system - which requires 55% support of member states representing 65% of the EU population - with a method giving each country votes based on the square root of its population.
