Ousted former Thai Prime Minister Yingluck Shinawatra gestures as she arrives at the Supreme court in Bangkok, Thailand, May 19, 2015. [Photo/Agencies]

BANGKOK - Thailand's former Prime Minister Yingluck Shinawatra entered a plea of not guilty Tuesday at the start of a trial that could see her jailed for a decade, which critics say is part of a politically motivated campaign against her family.

Supporters chanted "Yingluck! Yingluck!" as the ex-premier entered the Supreme Court in Bangkok to be formally read the charges against her of dereliction of duty in overseeing a rice subsidy scheme that lost billions of dollars.

"I am confident in my innocence," Yingluck told reporters. "I hope the court will grant me justice, and that everything will go according to due process under the law."

Yingluck was ousted from her post as prime minister by a court decision that came two weeks before the military staged a coup last May.

She is being charged with dereliction in overseeing the controversial rice subsidy program, which temporarily cost Thailand its crown as the world's top exporter. The same charges also led to her impeachment in January by the military-appointed legislature, which banned her from politics for five years.

She faces up to 10 years in prison if found guilty, a ruling that would deepen the country's decade-long political crisis.

Her supporters see the case as part of an attempt by the pro-establishment elite to dismantle the political legacy of her family, which has repeatedly won landslide victories in several general elections over the last decade.

The program was a flagship policy that helped Yingluck's Pheu Thai Party win elections in 2011, and Yingluck has argued it was aimed at helping poor farmers who were paid about 50 percent above what they would get on the world market. The program, however, racked up losses of at least $4.46 billion as the Thai government stockpiled mass quantities of rice. Prosecutors said Yingluck ignored multiple warnings from several state agencies about possible corruption - none of which has yet been proven in court.

Earlier this year, the National Anti-Corruption Commission recommended that the Finance Ministry sue her personally for at least 600 billion baht ($18.4 billion).

Thailand has been plagued by political turmoil that boiled over after the army ousted Yingluck's brother, former Prime Minister Thaksin Shinawatra, in a 2006 coup. That putsch was part of a societal schism that in broad terms pits the majority rural poor, who back the Shinawatras, against an urban-based elite establishment supported by the army and staunch royalists who see Yingluck's family as a corrupt threat to the traditional structures of power.

Yingluck's opponents argue the Shinawatras have used their electoral majority for personal enrichment and to subvert democracy.

Tuesday also marks the fifth anniversary of a bloody army crackdown against demonstrators backing the Shinawatras who had occupied downtown Bangkok for two months. More than 90 people were killed in the protests.