The NACC announced its decision to charge Ms Yingluck for dereliction of duty in relation to the rice scheme last month.
The caretaker premier was called to acknowledge the charge at its office in Nonthaburi on Feb 27, but assigned her lawyers to go on her behalf.
Under the rules of the anti-graft agency, Ms Yingluck can offer an explanation on the matter within 15 days of acknowledging charges, or by March 14.
She is permitted to testify by herself or can submit an explanation letter, according to the NACC.Caretaker Science and Technology Minister Peerapan Palusuk and a Pheu Thai legal adviser said the premier is likely to seek the agency’s approval to postpone the testimony date, since a large number of documents related to the rice programme must be compiled and prepared for her defence.
On Tuesday, Ms Yingluck's lawyer went to the NACC's office to ask permission to copy documents relating to the investigation on her behalf, saying the premier could not do so herself because of ongoing political problems and work in the North of the country. The NACC approved the request later that day.