NACC secretary-general Sansern Poljieak said on Thursday that the anti-graft agency settled for a 14-day delay for Ms Yingluck in a meeting on Wednesday.
Ms Yingluck sought 45 more days in a request submitted by her lawyer Norawit Lalaeng, citing more time was needed to prepare evidence to clear herself of the charges.
The NACC announced its decision to charge the prime minister with dereliction of duty on Feb 18.
Ms Yingluck chairs the National Rice Policy Committee.
The charges against her followed the NACC's decision to charge 15 people involved in the scheme, including former commerce minister Boonsong Teriyapirom and his deputy Poom Sarapol.