The tribunal announced the decision on Wednesday.
Mr. Saraki's trial was on May 25 adjourned till Wednesday, for the cross-examination of the witness, Michael Wetkas, to continue.
The tribunal chairman, Danladi Umar, said the adjournment was to give the court time to hear other cases.
The prosecution and defence teams also said the break would allow them prepare their cases better.
A court official, who asked not to be named, told PREMIUM TIMES Mr. Wetkas was attending another trial at the Federal High Court, Abuja.
The development is coming a day after an expected ruling on Mr. Saraki's case at the Court of Appeal, Abuja, stalled after the court failed to form a quorum.
The tribunal's spokesman, Ibrahim Alhassan, later told PREMIUM TIMES that the decision was taken at the instance of the prosecution counsel.
"He said his prime witness one is to appear before another court to testify against another high-profile personality today in Abuja," Mr. Alhassan said.
"Tribunal chairman was initially resistant to the request but we later asked them to make a formal request in writing and suggest a date which the tribunal would look into and take decision at its convenience. As I am writing you, I don't have the knowledge of whether the letter has come to CCT or not."