Some 40 mistakes in the Polish version of the proposed new European Union Constitution could delay progress towards its ratification, officials admitted as the opposition Wednesday slated "flagrant errors."

The foreign ministry said it had drawn up a full list of translation mistakes after comparing the Polish version with those of four other languages.

"More than 40 mistakes have been identified," said Deputy Foreign Minister Jakub Wolski. "We now have to apply the existing correction procedures."

Pawel Swieboda, head of the ministry's European department, acknowledged that correction work could cause parliamentary delays.

"The government wanted to submit the (constitution) treaty at the beginning of February but we'll now have to wait a further three to four months," he admitted to the newspaper Rzeczpospolita.

Poland's right-wing opposition sharply criticised the mistakes.

"The Polish government has signed a treaty containing flagrant errors which make it impossible to implement the treaty," said Kazimierz Ujazdowski of the centre-right Law and Justice party.

"These are not just simple linguistic mistakes, but passages containing (legal) dispositions that differ from other linguistic versions," PAP news agency quoted him as saying.

The deputy quoted one passage concerning voting in which a simple majority was apparently confused with a qualified majority.

Bronislaw Komorowski of the liberal opposition Civic Platform, tipped as favourite in the next general election, said parliament could not base itself on a constitution text that was not faithful to the original.

The EU constitution will be put to a national referendum in Poland. This poll will be prepared by parliament after an examination of the country's own national constitution, or basic law.

The referendum date has not yet been fixed. President Aleksander Kwasniewski and the left-of-centre government say it will be in the autumn, but the right-wing opposition wishes it put back to 2006.

The governments of the EU, which Poland joined last May, signed the treaty governing the constitution in Rome in October.

The constitution, agreed in June after two years of haggling, aims to streamline EU institutions and prevent decision-making gridlock in a bloc which grew from 15 to 25 members this year, with several more waiting in line.