UPDATE 1-Argentine Congress debates media reform law

* Lower house debates media law into the night

* Opposition walks out on discussion

* Deputies expected to approve bill after key changes

* Leftist Latin American leaders at odds with media (Updates with opposition walkout, debate extended, adds opposition quote)

By Luis Andres Henao

BUENOS AIRES, Sept 16 (Reuters) - Argentina's lower house was debating late into the night on Wednesday President Cristina Fernandez's broadcast reform bill, which is expected to pass even though opposition deputies walked out in protest.

The bill, which critics say will give the state too much control over the media and which supporters say will make the airwaves more democratic, has pitted Fernandez against the Clarin (CLA.BA) media group in her latest showdown with a powerful business sector.

The Chamber of Deputies was expected to vote on the bill early on Thursday after more than 12 hours of debate and if approved as expected, it will go to the Senate where it may have a tougher time getting through.

"We are convinced we will have enough votes," Deputy Agustin Rossi, head of the president's Victory Front faction of the Peronist party in the lower house, told reporters.

Center-left leader Fernandez says her reform of decades-old media regulations will allow smaller players and nonprofits more access to frequencies and restrict the number of licenses to dominant media players.

Critics say her main motive is to crush the influential Grupo Clarin conglomerate, and opposition politicians also question elements of the reform such as the way the state will be able to assign frequencies in small cities and towns.

Opposition lawmakers boycotted the debate on the lower house floor, saying the government had rushed the bill through committee without proper review. The government is still expected to have enough votes to pass the law.

"It's a farce. There has not been a proper debate of something that is a transcendent law ... we couldn't even finish reading it," Deputy Adrian Perez, head of the Civic Coalition opposition party in the lower house, told TN television.

DISPUTE WITH MEDIA GROUP

Fernandez and her husband, former President Nestor Kirchner, have been locked in a bitter dispute with Grupo Clarin since its news outlets criticized their confrontation with farmers last year, over taxes on grains exports.

Fernandez, known for her uncompromising style and for increasing state control of some parts of the economy, tried to smooth passage of the law by removing a controversial clause that would have allowed some telephone companies to enter the cable television business.

She said eliminating that element of the bill should dispel opposition concerns that telecommunication companies would become too dominant in telephone, cable and Internet all together.

But dissident Peronists, center-right parties and even the center-left Civic Coalition opposition party were not swayed by the changes to the law and made a failed attempt to delay the vote until December when a new Congress will be seated.

Fernandez's bill comes against a backdrop of leftist leaders in Bolivia, Ecuador and Venezuela strengthening state media outlets and warring with traditional newspapers and broadcasters that have given their administrations deeply negative coverage.

In Venezuela, socialist President Hugo Chavez has shut down radio stations and denied renewal of broadcast licenses. Fernandez's reform is not seen as so radical.

"Approval in the Senate will be difficult but, at this point, we believe the Senate will likely end up approving the bill, perhaps after further concessions from the government," said Daniel Kerner, a Latin America analyst for the Eurasia group. (Editing by Fiona Ortiz and Peter Cooney)