Ms Yingluck raised her concerns after giving her verbal defence before the National Anti-Corruption Commission (NACC) on Monday. She has asked the agency to question 11 more witnesses, but the NACC allowed only three of them to testify before Songkran begins on April 12.
With a limited timeframe and a reduced number of witness, Ms Yingluck said she is worried by the matter but will use existing mechanisms to defend herself to the utmost.
She insisted that the allegations against her are untrue.
Following the Constitutional Court's decision to consider a petition against her over alleged unconstitutional transfer of National Security Council (NSC) chief Thawil Pliensri to an inactive post, Ms Yingluck expressed hope that the court will apply the so-called one standard practice to rule the case.
Ms Yingluck pledged that she followed all procedures in transferring Mr Thawil.
The Supreme Administrative Court ruled last month that the removal of Mr Thawil from his previous NSC post was unlawful and ordered to reinstate Mr Thawil in 45 days. A group of 28 senators led by Paiboon Nititawan later petitioned the Constitution Court to rule on the status of Ms Yingluck and whether she has breached the constitution in the case.