Prague  - Czech parliament's lower house is due to start debating the European Union's reform treaty on December 9, an official said Monday.

Lower house speaker Miloslav Vlcek called an extraordinary session on the Lisbon Treaty at the request of the opposition Social Democratic Party, which backs the charter.

The Czech Republic, which assumes the EU presidency on January 1, is the last member state to vote on the accord, which has been stalled since Irish voters rejected it in a June referendum.

The country's Constitutional Court ruled elements of the treaty in line with Czech law on November 26, opening the door to its ratification in the Czech parliament.

The pact faces opposition of the eurosceptic wing within the senior governing Civic Democratic Party led by Prime Minister Mirek Topolanek, who reluctantly signed the treaty on behalf of the Czech Republic in December 2007.

On Sunday, Topolanek warned against voting on the treaty before the year-end as it could be rejected by some of his lawmakers in the lower house.

Topolanek hopes to nail his party's support for the pact, aimed to streamline decision-making in the 27-member union, at Saturday's party congress that is so far expected to re-elect him the party leader.

Treaty's ratification in the Czech Republic also requires an upper house and presidential approval.

Czech President Vaclav Klaus, a fierce critic of the accord and deeper European integration, has said that he will sign the pact only after Ireland reverses its rejection. (dpa)