Caretaker Deputy Prime Minister and Finance Minister Kittiratt Na-Ranong says he may not be able to testify in the rice-pledging case on Friday.
Mr Kittiratt is among three additional witnesses caretaker Prime Minister Yingluck Shinawatra presented to the National Anti-Corruption Commission (NACC) to provide statements in her defence.
The other two ministers are caretaker Deputy Prime Minister and Commerce Minister Niwatthamrong Bunsongphaisan, and caretaker Deputy Commerce Minister Yanyong Phuangrach.
The NACC wants the three cabinet ministers to testify in the rice-pledging case before the long Songkran holiday starts on Saturday and ends next Wednesday.
Ms Yingluck has been charged by the NACC with failing to take action against alleged irregularities in the rice scheme.
The caretaker prime minister is facing the charge that she, as chairwoman of the National Rice Policy Committee, failed to oversee the scheme properly and did not act against alleged corruption.
If the NACC indicts her, she is required to suspend her duties as premier.
Mr Kittiratt said yesterday he will have to attend the meetings of the World Bank and International Monetary Fund in Washington from tomorrow until Friday.
He said he will today fly to attend the meetings first, but if the NACC insists on hearing testimony from him by Friday, he will be obliged to return.
Mr Kittiratt also gave an assurance that the caretaker government can pay back the 20-billion-baht loan to the central budget by the end of May so as not to incur any financial liabilities for a new administration.
The amount is sufficient to pay overdue debts to about 170,000 rice farmers.
The Election Commission endorsed the 20-billion-baht loan from the Central Fund earlier last month on condition that the loan be settled by May 31.
Mr Niwatthamrong said yesterday he was compiling documents to use as evidence when he testifies to the NACC.
He said the anti-graft agency will summon him to give statements on Thursday while Mr Yanyong will testify tomorrow.
The prime minister previously named 11 additional witnesses in the case, but the commission limited the number of witnesses to just three.
Mr Nitwatthamrong said Ms Yingluck's legal team will try to ask the NACC to allow it to present more witnesses in her defence.