By Daria Sito-Sucic

SARAJEVO (Reuters) - The failure of Bosnia's political leaders to make progress on reforms sought by the European Union will further delay the Balkan country's application for the membership of the bloc, the EU enlargement chief said on Tuesday.

Bosnia has planned to apply for the membership of the 27-nation bloc this year but bickering among its ethnic Bosniak (Bosnian Muslim), Serb and Croat leaders has repeatedly stalled reforms since 2008, when the country signed its association contract with the EU.

Disputes over the budget have forced yet another delay.

Bosnia and Kosovo are the only countries from the Western Balkans region that have not yet applied for the EU membership.

Neighboring Croatia is set to join next year, while Albania, Macedonia, Montenegro and Serbia have all applied for membership and are at different levels of integration.

The main condition for Bosnia to send what EU officials call a "credible application" was to harmonize its constitution with the European Charter on Human Rights to end discrimination of minorities who cannot run for high offices.

This has not been done, even though the Strasbourg-based European Court of Human Rights ordered Bosnia three years ago to amend the constitution to allow minority groups, such as Jews or Roma, to run for the presidency.

Bosnia has been governed along ethnic lines since the 1992-95 war which killed an estimated 100,000 people and split the country into two autonomous regions, linked via a weak central government.

Under the U.S.-brokered Dayton peace accords that ended the war, only Bosniaks, Croats and Serbs are regarded as so-called "constituent peoples" who can apply for top government jobs - a provision that discriminates other groups.

"Representatives of Bosnia-Herzegovina have not been able to honor the main commitments they've taken themselves," EU Enlargement Commissioner Stefan Fuele said.

"It's clear that this will delay the European Union integration of your country," Fuele said, after meeting the country's leaders for talks aimed at review the progress of reforms agreed under an EU road map for Bosnia in June.

An inconclusive election in 2010 led to more than a year of political paralysis as rival ethnic leaders argued over how to form a national government.

The impasse was broken at the end of 2011 and a government elected in February but divisions over the budget have forced a reshuffle, with the battle over power and patronage pushing reforms off the agenda once again.

A new, six-party parliament majority approved the government last week, replacing the main Bosniak SDA party with the Party for Better Future (SBB) of media tycoon Fahrudin Radoncic, who was sworn in as new security minister.

A new defense minister and a deputy finance minister were elected from the ranks of SBB and the Social Democratic Party (SDP), who joined an alliance comprised of two Serb and two Croat nationalist parties.

A new coalition pledged to pursue reforms but have not submitted any concrete proposals to the government yet.

(Reporting by Daria Sito-Sucic; Editing by Alison Williams)