Colombia court sees re-election ruling next year

* Time is tight for Uribe's bid for third term

* Re-election referendum is being challenged in court

BOGOTA, Oct 23 (Reuters) - Colombia's constitutional court likely will not rule until next year on President Alvaro Uribe's re-election bid, complicating the time frame for the U.S. ally to secure a third term, the court's chief said on Friday.

Colombia's Congress has approved a referendum on whether to amend the constitution to allow Uribe a third consecutive term. But the court has yet to rule on the legality of the process to clear the conservative for another run in May next year.

Electoral authorities say once the court makes its ruling, they will need at least two months to organize the re-election referendum.

Uribe, who was re-elected to a second term in 2006, has been evasive on whether he will run, but his allies have pushed hard for a third term for a president popular for his campaign to defeat leftist rebels fighting a four-decade-old conflict.

Constitutional Court President Nilson Pinilla said the amount of evidence and the court's calendar meant judges won't be able to debate re-election until after year-end vacations. The court is also waiting for the magistrate in charge, Humberto Sierra, to have documents in the case ready.

"We're back on Jan. 12. It is possible at that moment Mr. Sierra will have the documents ready... and the court can study and discuss the matter from then. There are points in the calendar that are insurmountable," Pinilla told local radio.

The attempt to reform the constitution to allow Uribe to run again has fueled concern over Colombia's democracy, with critics already branding the president a would-be authoritarian determined to extend his time in power.

His leftist Andean neighbors, Venezuelan President Hugo Chavez and Ecuadorean leader Rafael Correa, have rewritten their constitutions to lift limits on re-election, sparking criticism from opponents over their commitment to democracy.

The court will examine several challenges to the referendum, ranging from questions over the financing of the campaign to collect signatures in favor of the vote to complaints over the legality of the decision in Congress.

Uribe, the son of wealthy landowners, has said he is at a "crossroads of the soul" over whether to run for re-election, balancing what he sees as his role in defeating the FARC guerrillas against the criticism that another term would undermine democracy.

Editing by Eric Beech