Jamila Delalic reacts after judges at the Yugoslav War Crimes Tribunal adjourned the trial of Radovan Karadzic, after he boycotted his trial in The Hague on Monday. (Peter Dejong/Associated Press)

The war crimes trial of former Bosnian Serb leader Radovan Karadzic has been abruptly adjourned after he boycotted the opening day.

UN Judge O-Gon Kwon noted the absence of Karadzic or of any defence attorneys representing him as the International Criminal Court trial at The Hague began on Monday.

The three-judge panel agreed to adjourn the trial after meeting for about 15 minutes. It will recommence Tuesday afternoon and will proceed even if Karadzic or his defence do not appear, the judges said.

A view of the seat where former Bosnian Serb leader Radovan Karadzic was supposed to have sat when attending the start of his trial on Monday. (Peter Dejong/Reuters)

"There are circumstances in which trials can proceed in the absence of the accused who has voluntarily waived his right to be present," Kwon said.

There were some cries of anger and tears from a group of survivors of Bosnia's 1992-1995 war who had gathered in the small gallery before the tribunal.

"We are shocked," Admira Fazlic, who was imprisoned in Bosnian Serb-run camps during the conflict and had travelled by bus to see the start of the trial. "Radovan Karadzic is making the world and justice ridiculous. He is joking with everybody."

The prosecution was scheduled to present its case Monday and Tuesday. Karadzic, who is representing himself, had been scheduled to outline his case next week.

Prosecutor Hildegard Uertz-Retzlaff urged judges not to allow Karadzic to deliberately hold up the trial, which is expected to take more than two years. There are more than one million pages of prosecution documents and hundreds of witnesses are expected to testify.

Karadzic was arrested on a Belgrade bus in late July 2008 after 13 years on the run. At the time, he had flowing white hair and a bushy beard and was working as a new-age healer under the name of Dr. Dragan Dabic.

'Not be a trial at all'

Kwon said if Karadzic continued to be absent, judges would consider appointing a lawyer to represent him.

Former Bosnian Serb leader Radovan Karadzic faces trial at a UN court in The Hague for charges including genocide and crimes against humanity. (Valerie Kuypers/Associated Press)

Karadzic had stated ahead of the trial that he would boycott proceedings and had asked for an additional 10 months to prepare.

Karadzic sent a letter to the court last week saying he would not attend the trial until he was ready, and would let the court know several weeks in advance when that would be.

"If I am not prepared that would not be a trial at all," Karadzic wrote. "There must be a fair solution."

The trial of the Bosnian Serb leader is considered one of the most significant war crimes cases since the Second World War.

His refusal to show up is a blow to survivors who hold him responsible for tens of thousands of deaths during the brutal 1992-95 Bosnian war. It left more than 100,000 dead, most of them victims of Bosnian Serb attacks.

11 counts of war crimes

The case before the International Criminal Tribunal comes as a relief after the trial of Karadzic's former political mentor — Slobodan Milosevic — collapsed without a verdict after he died in 2006.

Karadzic, 64, is charged with 11 counts of war crimes, including two counts of genocide, for allegedly masterminding atrocities during the Bosnian war, including the 1995 massacre of about 8,000 Muslim males in Srebrenica and the deadly siege of Sarajevo.

He has repeatedly refused to enter a plea but claims innocence on all charges and has fought to have the charges against him dropped based on claims he was offered immunity if he left public life.

Karadzic faces a maximum sentence of life imprisonment if convicted.

With files from The Associated Press