(WARSAW) - Poland's President Lech Kaczynski has approved a law ratifying the EU's Treaty of Lisbon, after lawmakers backed the accord meant to streamline the 27-nation bloc, his office said Thursday.

Kaczynski's move cleared a final hurdle in Poland's ratification of the treaty, after both houses of parliament approved it last week following wrangling between the liberal government and eurosceptic opposition.

The law passed by parliament authorised the president to ratify the treaty.

All that remains, under the Polish constitution, is for the head of state to put his signature on a separate act of ratification, officials explained.

The Lisbon Treaty, which replaces the EU constitution scuppered by French and Dutch voters in 2005 referendums, has to be ratified by all 27 member states if it is to come into force, as planned, by 2009.

The treaty, adopted by EU leaders last December, is designed to smooth the running of the bloc, whose membership has almost doubled since 2004.

To date, it has also been ratified by lawmakers in Austria, Bulgaria, France, Hungary, Malta, Romania and Slovenia.

Earlier this year it had appeared that Poland, the largest of the ex-communist newcomers to the EU in 2004, could upset the reform process this time.

Prime Minister Donald Tusk, lacking the two-thirds parliamentary majority needed to push through the ratification, spent weeks sparring with the president and his twin brother, opposition leader Jaroslaw Kaczynski.

The Kaczynskis had demanded additional legal guarantees before giving a green light for ratification, arguing that Poland's interests would otherwise be in danger.

They notably attacked the Charter of Fundamental Rights, tied to the Lisbon Treaty, claiming it could pave the way for gay marriages in Catholic Poland and the restitution of properties lost by Germans after the Polish-German border was redrawn by World War II Allies in 1945.

Poland, like Britain, secured an opt-out from the charter, a wide-ranging accord on human rights and freedoms.

The Kaczynskis argued Tusk's ratification bill failed to adequately protect the opt-out, but backed off from a threat to torpedo it after finding themselves out of step with public opinion.

Tusk had raised the spectre of a referendum should the bill fail in parliament -- and opinion surveys suggested 65 percent of Poles would back the treaty.

The brothers' stance drew additional criticism because both had been involved in drafting the EU treaty last year, before Jaroslaw Kaczynski lost office to Tusk in a snap election in October, and had at the time trumpeted the treaty as a success.

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