Members of the League of Polish Families, which forms part of Poland's right-wing coalition government, have said they will oppose adoption of the new treaty as it does not comply with Polish family values and national interests, according to news reports.

"We will appeal to the public and to Law and Justice not to ratify the treaty," said the League's leader, Deputy Prime Minister Roman Giertych, referring to the conservative party of President Lech Kaczynski and Prime Minister Jaroslaw Kaczynski. "We will start a campaign against the treaty because, thanks to Germany, it includes amendments which are putting EU interests ahead of Poland's interests."

It is still not clear whether Poland will ratify the treaty via referendum or through parliamentary approval.

The treaty will create an EU president and a foreign policy chief and make it easier to reach decisions in the long term by changing the current unanimous voting structure. The agreement, however, falls short of an EU constitution, the draft of which was rejected by French and Dutch voters and faced strong resistance from Poland's twin leaders.

According to Reuters news service, the League has been blamed for the rise of xenophobia and racism in Poland by the European parliament. The party opposed the country's EU membership in 2004 and has long held anti-German views.

No more negotiations

EU Commission President Jose Manuel Barroso meanwhile said that there was no way to restart negotiations on the treaty, which leaders from the 27-member EU agreed to in June.

"None of the issues which were agreed upon can be reopened again," Barroso told journalists during a visit to Portugal to mark the beginning of the country's EU presidency.

Portugal is now in charge of drafting the new treaty, which Portuguese Prime Minister Jose Socrates aims to have ready by October.

"The Portuguese presidency has received a mandate to produce a new treaty, and in the mandate it doesn't say: 'Oh, by the way, you can revise the mandate,'" said Socrates at the same news conference with Barroso. "I don't think it makes any sense nor do I see any country that wants to question" the mandate.