At the inauguration of a new floating market on Thursday, Prime Minister Prayut Chan-o-cha said ex-premier Yingluck Shinawatra, seen here shopping in Chiang Mai, must remain in Thailand to see her trial through to the end. (Photos by Apichart Jinakul)

Prime Minister Prayut Chan-o-cha has urged former premier Yingluck Shinawatra to step forward and prove her claims of innocence in the face of the charge against her of dereliction of duty in the rice-pledging scheme.

Gen Prayut on Thursday suggested Ms Yingluck remain in the country and stay within the legal process.

"If you think you are innocent, you should obey the rules. If you do not obey the rules and say that what you did was correct, how can people accept this? Conflict will only follow," Gen Prayut said.

"Ms Yingluck once told me that she was ready to fight. So, she should choose a course of action that complies with the law and the justice system. The judicial process is under way and is ready to deliver justice," Gen Prayut said.

The National Anti-Corruption Commission (NACC) filed a lawsuit with the Office of the Attorney-General (OAG), accusing Ms Yingluck of dereliction of duty for failing to stop losses and corruption in her government's rice programme, in violation of Section 157 of the Criminal Code and the National Anti-Corruption Act.

Ms Yingluck is due to report to the OAG on Thursday. From there, she will be taken to the Supreme Court's Criminal Division for Political Office-Holders to be formally indicted over the rice scheme.

However, Gen Prayut admitted that he was not sure whether Ms Yingluck would fight her case all the way to the end, despite assurances given by her lawyer, Norawit Lalaeng, that she would not flee and would proceed with the case.

But Gen Prayut said he will hold Mr Norawit responsible if anything goes wrong.

Winyat Chartmontri, another one of Ms Yingluck's lawyers, told the Bangkok Post that the former premier can ask the OAG to postpone her indictment if her reasons are adequate. It is up to the OAG to consider how long the indictment should be postponed for, Mr Winyat said.

He said it is still not known if Ms Yingluck wants a postponement and whether she will report to the OAG on Thursday.

Mr Norawit on Thursday submitted a petition to the OAG asking that prosecutors reconsider the decision to indict his client over the rice scheme.

The petition letter was received by Kittinant Thatpramuk, deputy director-general of the OAG's Investigation Bureau.

Mr Norawit said the OAG was also asked to further investigate certain points about the rice-pledging case.

For example, a joint committee of the OAG and the NACC found the inquiries into some points of the case were incomplete, but the NACC had not made additional inquiries as asked by the joint committee, according to the lawyer's petition.

Mr Norawit also said that under the law the defendant is not required to report to the OAG on Thursday.

He also dismissed as groundless earlier speculation that Ms Yingluck would seek political asylum overseas. Her legal team has not discussed this matter, he said.

Mr Kittinant admitted the OAG wrote to Gen Prayut, recommending that Ms Yingluck not be allowed to travel abroad.

The recommendation was made after the National Council for Peace and Order sought the OAG's advice on the matter, Mr Kittinant said.

Citing intelligence reports, deputy government spokesman Sansern Kaewkamnerd said Ms Yingluck is still residing at her home in Chiang Mai, countering reports that she was seeking asylum abroad.

Maj Gen Sansern also insisted that the charges against Ms Yingluck are not politically motivated, but are criminal and civil charges pending judicial procedures.

He denied suggestions that certain groups of individuals are being singled out for persecution. People from rival political camps now face legal proceedings for their actions, said Maj Gen Sansern.

Asked whether red-shirt United Front for Democracy against Dictatorship leader Jatuporn Prompan's remark on TV about the legal process against Ms Yingluck could be considered as an attempt to incite political unrest, Maj Gen Sansern said anyone who makes political comments to incite unrest will be "invited for discussions".

Mr Jatuporn told a TV programme on Wednesday that if Ms Yingluck is prosecuted and imprisoned, red-shirt supporters would come out to protest and literally stage a prison break.

"It's not that [we think] only one person breaking the law can make the entire country fail. We have always played by the rules. But how much do those people accept the truth? If they stop and think about what they have done and how society has reacted to their actions, they will understand that no one is persecuting them at all," Maj Gen Sansern said, responding to Mr Jatuporn.