A military-appointed legislature in Thailand will decide on Friday whether to ban the former prime minister Yingluck Shinawatra from politics over a botched rice subsidy scheme – a move that analysts say is aimed only at further consolidating power and could provoke fresh violence.

The impeachment proceedings relate to a popular but troubled scheme to pay farmers double the market price for their rice crop. The scheme is believed to have incurred losses of around £10bn.

Thailand’s anti-corruption agency has agreed to press criminal charges against Yingluck, a hugely popular leader who was ousted from power just before a military coup on 22 May last year. She could face up to 10 years in prison and a five-year political ban if found guilty of negligence and corruption for her role in the subsidy.

Pavin Chachavalpongpun, a Thai political analyst at Japan’s University of Kyoto, said the charges were an “obvious ploy to get rid of the Shinawatras” rather than a viable case. He said the hearings could trigger instability and political violence, thereby jeopardising the army’s hold over Thailand, which has been under indefinite martial law since May.

“The military staged a coup to overthrow her, then set up a legislative committee to impeach her,” Pavin told the Guardian, adding that the decision seemed pre-determined. “The NLA [national legislative assembly] has been designed to be an anti-Shinawatra unit. Impeaching Yingluck is its main responsibility.”

Yingluck herself has described the timing of the proceedings as “weird” given that she is no longer in office, while former ministers from her administration have pledged their support via YouTube after they were barred from speaking on her behalf during a hearing last week.

The ousted officials claim the scheme boosted growth in the agricultural north, where millions of farmers voted for Yingluck in a landslide 2011 election. But after reports of corruption and mismanagement, thousands of tonnes of unsold rice rotting in silos, and suicides among bankrupted farmers, the scheme fell out of favour.

Thailand’s anti-graft agency has also charged the former commerce minister Boonsong Teriyapirom and 20 other colleagues with collusion in government-to-government rice contracts involving Chinese firms that were not authorised for involvement, local media reported.

The prime minister, Prayuth Chan-ocha, who assumed power in the May coup, has warned the Thai public not to engage in any protests during Friday’s proceedings and said the hearings would provide insight into the previous government’s dealings. “The case will be an indicator to measure ethics and leadership of politicians in the [previous] government,” his deputy spokesman Sansern Kaewkamnerd quoted Prayuth as saying.

The handpicked legislative assembly will also hold impeachment proceedings against a former house speaker and a former senate speaker for allegedly trying to change the constitution, which was suspended when the army seized power.

Analysts say the move is intended to keep the Shinawatra family out of politics for as long as possible, or at least through the next election. Shinawatra-linked parties have won every poll in the past decade and it is expected that the military government will hold elections again this year, although it is unclear exactly when.

Thitinan Pongsudhirak, director of Thailand’s Institute of Security and International Studies, said the proceedings were part of a political saga, the focus of which was not Yingluck or her policies but the legacy and power of her self-exiled brother Thaksin, a former telecoms tycoon who was ousted as premier in another military coup in 2006.

“The rice-pledging [scheme] was a fiscal disaster and so there was some ground to these machinations, but this is really about a raw power play,” Thitinan said. “Sidelining Yingluck would level the playing field for Thaksin’s opponents … [but] this impeachment will likely rack up more grievances which will be suppressed and will likely be more intense when they surface.”

The proceedings could spell disaster for policymakers in Thailand in the future, he said, as they sent a bleak message that those who try to implement policy could face impeachment or imprisonment.

Whether or not the assembly finds Yingluck guilty of wrongdoing is unlikely to hold too much sway over Thailand’s long-term politics, according to Pavin, even if she is banned from elections for the next five years and Thaksin remains in self-exile in Dubai.

“Thaksin has proven that he can pick anyone to be in his shoes,” he said. “Without Yingluck, so what? This will not be the end of the Shinawatras.”