The trial was to have resumed on June 25.
"Trial Chamber I suspended the start of presentation of the Prosecution's evidence in the case of Ratko Mladic until further notice," a statement said, adding that the "Chamber's full decision and reasoning will be made public in due course."
On May 31, the defence asked that the trial be postponed for six months, saying it did not have enough time to prepare and warning about irregularities in the disclosure of the prosecution's evidence. The prosecutor's office admitted that errors had been made, saying it did not object to a suspension.
The 79-year-old Mladic was arrested in Serbia on 26 May 2011 after 16 years on the run. He was accused of genocide, crimes against humanity and war crimes committed during the 1992-95 Bosnian war in which 100,000 people were killed and 2.2 million were displaced.