Prime Minister Prayut Chan-o-cha said on Friday he had cautioned Yingluck Shinawatra over the rice-pledging scheme when he was in still army chief.
Gen Prayut said he raised the issue in talks with the then-prime minister when he was the army chief and more criticism was being heaped on the controversial scheme, which was a flagship policy of the Pheu Thai Party.
The criticism centred on corruption and massive losses to the state from the scheme, under which the government bought rice from farmers at prices way above the market value.
Gen Prayut said they talked about the project when he was army chief and before he led the military coup in May last year. He did not say exactly when he warned her of the problem.
''I told her there would be problems and and she said it was all right because she was determined to follow through on the policy and had evidence to counter the critics,'' the prime minister said. He then told her: ''Then it's up to you.''
Ms Yingluck faces likely indictment on a criminal charge on dereliction of duty in failing to heed warnings about corruption in the rice scheme and about the mounting financial loss to the state while prime minister.
Prosecutors plan to submit the case to the Supreme Court's Criminal Division for Holders of Political Positions next week.
Ms Yingluck, who is in Chiang Mai, and her lawyers have said she will fight the case in court.