The war crimes trial of Bosnian Serb ex-army chief Ratko Mladic, abruptly halted after one day, should be delayed "for weeks rather than months," the UN court's chief prosecutor said Tuesday.

"We have not opposed the request by the defence to have the presentation of evidence delayed for some time, but we are more thinking about the number of weeks and not the number of months," said Serge Brammertz, the chief prosecutor of the International Criminal Tribunal for the former Yugoslavia (ICTY).

However, "it is very important that... we give the right dimension to the problem. So we think it's four weeks, or six weeks or eight weeks, but not six months which are requested by the defence," Brammertz told reporters during a visit to Belgrade.

Just a day after the trial opened last week in The Hague the presiding judge Alphons Orie announced that it was adjourned indefinitely due to "irregularities" in the transfer of prosecution documents to the defence to enable it to prepare for the trial.

Brammertz said the prosecution "have recognized the problem, we found it also very unfortunate, but we addressed it immediately."

"We have filed yesterday (Monday) a motion with all the figures and information in relation to this disclosure issue," he said.

According to the prosecutor, last year his office had failed to upload attachments to about three percent of some 100,000 documents disclosed.

Mladic, the so-called "Butcher of Bosnia", is charged with 11 counts of war crimes, crimes against humanity and genocide over the 1992-1995 Bosnian war, in particular the Srebrenica massacre of almost 8,000 Muslim men and boys.

Prosecutors also hold Mladic responsible for the 44-month siege of Sarajevo that left an estimated 10,000 people dead, the vast majority of them civilians.

Mladic, who was arrested a year ago in Serbia after more than 16 years on run, pleaded not guilty to the charges at an earlier court hearing. He faces life imprisonment if convicted.