BRUSSELS (AFP) - Swedish Prime Minister Fredrik Reinfeldt warned the Czech Republic of the costs of further delaying the EU reform treaty as the eurosceptic Czech president holds out against the pact.

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But Czech Prime Minister Jan Fischer, who held talks with Fredrik Reinfeldt and other top EU officials, said his country should ratify the treaty by the end of the year.

With the Lisbon reform treaty meant to enter force next year, Reinfeldt said the 27-nation EU is entering unchartered waters.

"We are moving into unknown territory," he told reporters after a video conference with Fischer.

"A lot of Europeans are waiting for this to be solved and we are trying to do it as quickly as possible," said Reinfeldt, whose nation holds the EU's rotating presidency until the end of the year.

The Czech parliament has approved the treaty, which is intended to ease EU decision-making, and Fischer opposes President Vaclav Klaus' campaign against the pact.

Fischer expressed confidence that Klaus would sign it once a Constitutional Court review of the treaty has been cleared up.

"I believe that everything is in place for the ratification of the Lisbon Treaty to be fully completed in the Czech Republic by the end of this year," he said in Prague.

"I am fully convinced that after we have the ruling of the Czech Constitutional Court, the Czech president will be ready to complete the ratification."

The treaty cleared a significant hurdle last week when Irish voters approved it in a second referendum. Now the presidents of the Czech Republic and Poland are holding out.

Poland's President Lech Kaczynski is expected to sign the treaty into law within days. However Klaus, known for his bellicose rhetoric and unpredictability, has refused to endorse it, and is awaiting the outcome of the latest legal challenge before the country's Constitutional Court before making his next move.

EU officials are reluctant to pressure Klaus, with either a carrot or a stick approach likely to be seized upon by the eurosceptic head of state to reinforce his campaign.

"We prefer to talk about the climate change issue, about the costs of that. We prefer to talk about the unemployment rate, which is growing and we must stop it," European parliament head Jerzy Buzek said after the talks.

"So why are we discussing such a problem? The costs of that should be known to everybody," he said.

Indeed the EU has few weapons left. Reinfeldt said Wednesday that Klaus has refused to answer his phone calls since the Irish referendum Friday.

Sweden faces the unenviable task of laying the foundations for the reform package so that it can enter force next year.

The treaty creates a new EU president and foreign affairs supremo. But Reinfeldt ruled out starting consultations on the new posts created until the opinion of the Czech court becomes clearer.

An EU official said: "There is so much to be done, so much to be put in place. If this treaty is ever going to enter force next year, we have to start work now."

The document can only come into force when all 27 nations have ratified it.

The Czech Constitutional Court is reviewing a complaint filed by Czech senators -- most of them from Klaus's former party -- and expects to announce a date for the final ruling within three weeks.

Apart from the Czech Republic and Poland, Britain's opposition Conservative party has also caused some concern. Its leader David Cameron opposes the treaty but says he will not reopen debate if it has already been approved by the time an election is held next year.

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