Toppled Thai premier Yingluck Shinawatra was mobbed Friday by well-wishers, many bearing red roses, as she arrived for what could be the final hearing of a trial for criminal negligence that carries a 10-year jail term.

She is accused of failing to stop corruption in a rice subsidy policy that funnelled cash to her poor, rural farming base but cost the Thai exchequer billions of dollars.

Her supporters say the case is driven by the junta that overthrew her government in 2014 and is determined to expunge her super-rich clan from Thailand's political scene.

Her brother Thaksin, who heads the Shinawatra family, was toppled as premier in a 2006 coup and fled the country over corruption convictions.

Yingluck's case is the first time a Thai premier has faced charges for the outcome of an economic policy in a country where populist handouts are commonplace and military spending passes without serious scrutiny.

She wiped away tears as she embraced supporters and posed for pictures with the crowd of some 500 supporters massed outside of the Bangkok court, holding roses and balloons.

"I want to thank all of the media and people who came here to support me," she said in a brief comment to the press.

If the remaining witnesses are heard, Friday could see Yingluck give a final defence statement.

Once the trial is over judges have a month to deliver a verdict.

- Withering democracy -

Thailand's first female prime minister was impeached for abuse of power and banned from politics in the wake of the coup.

But she remains a galvanising force among her supporters, with the trial turning her into something of a martyr for a democracy movement that has withered under junta rule.

"People love the Shinawatra family because they helped small people get money and make a living," said Wachiraporn Laongnual, who said she travels two hours to attend every court hearing.

The farmers among the crowd outside the court defended Yingluck's rice policy, which saw the government pay nearly twice the market price for paddy.

"Under Yingluck's rice scheme the rice was bought by the government and farmers could live very well. Now it's a struggle," said Nantha Phunen, adding that she was swamped by debt amid low rice prices.

The former PM was joined by dozens of Pheu Thai politicians on the steps of the court, a rare a political gathering under tight junta controls.

The junta has vowed to hold elections next year.

But a new charter it scripted strips back the power of elected politicians and creates a fully appointed upper house.

The Shinawatras and their allies have won every general election since 2001, but their political networks have been battered by the coups and endless legal cases.

The Thai junta, which represents the royalist Bangkok-centric elite, refuses to accept the legitimacy of Shinawatra electoral victories, decrying their politics as venal and corrupt.

Yingluck also faces a civil action to claw back $1 billion in compensation for the rice subsidy program that paid farmers up to twice the price of their crop.

source: AFP