Besides Boonsong, three other former politicians and two senior commerce ministry officials were named in the case in connection with the rice-pledging scheme.

The allegedly fake government-to-government rice deals involving bogus Chinese buyers led to estimated damages of about Bt20 billion, according to a government report.

Earlier, Prime Minister Prayut Chan-o-cha told Apiradi to proceed with the controversial case before the statute of limitations expires in February next year.

Apiradi said the ministry would complete its task before the legal deadline, but needed to carefully study the details of the case.

The case is sensitive with several agencies involved.

Former premier Yingluck Shinawatra faces criminal and civil liability lawsuits similar to those facing Boonsong concerning the rice-pledging scheme, which suffered heavy losses, even though it was popular among farmers who benefited from high rice prices.