Ousted Thai prime minister Yingluck Shinawatra told supporters not to gather outside the country's top court on Friday when it rules whether she is guilty of negligence.
Thailand's first female prime minister, toppled by a military coup in 2014, faces up to 10 years in prison if convicted and a life ban from politics under the new military-drafted constitution.
Thousands of supporters were expected to turn up outside the Supreme Court in northern Bangkok for the ruling, raising the spectre of confrontations with the police.
The junta said it would mobilise more than 4,000 police and army officers to surround the court and warned against mass demonstrations.
In a Facebook post on Thursday, Yingluck told supporters to stay home, fearing people with "ill-intentions" might try and cause trouble for their movement.
"I want all of you to give me support by staying home and monitoring the news to avoid any risk of an unexpected incident by people with ill-intention against the country and us," she wrote.
Yingluck is on trial over her administration's rice subsidy scheme which paid farmers nearly twice the market rate for their crop.
Her previous court appearances have seen increasingly large crowds gather outside the court, showering her with roses and chanting -- a rare sight in a nation where political gatherings remain outlawed.
The subsidy scheme handed billions of dollars to her rural voter base but also allegedly led to massive graft and huge stockpiles of unsold rice.
The policy helped spark months of street protests in 2013-14 that called for and eventually secured the overthrow of her government.
Throughout her trial Yingluck defended the scheme, saying she acted in good faith to raise the incomes of the poorest and was the victim of "a subtle political game".
The military and prosecutors say she must take personal responsibility for the scheme, in an unprecedented move to punish a Thai leader for a policy.
Analysts say the junta and its establishment allies are bent on crushing the political machine led by Yingluck and her billionaire brother Thaksin Shinawatra, who was himself ousted in a 2006 coup.
The siblings are beloved in Thailand's poor northeast but loathed by Bangkok's traditional elite, who have hit their governments with coups or court rulings.
© 2017 AFP