UN prosecutors described harrowing scenes of rape and murder Tuesday as they sought an unprecedented conviction for genocide in Bosnian towns during the 1990s conflict against former Serb commander Ratko Mladic.

Once dubbed "the Butcher of Bosnia," Mladic, 74, has denied 11 charges including two of genocide, as well as war crimes and crimes against humanity for his role in the bloody 1992-95 Bosnian conflict.

More than 100,000 people died and 2.2 million others were left homeless in what prosecutors say was a relentless campaign of ethnic cleansing, aimed at chasing all non-Serbs from Bosnian territory with the aim of creating a Greater Serbia.

Prosecutors at the International Criminal Tribunal for the former Yugoslavia (ICTY), who are due to unveil their recommended sentence on Wednesday, outlined a litany of atrocities committed in the region, in towns such as Prijedor, now in northeastern Bosnia.

There was an "unmistakable" intent to destroy a community if "more than 1,500 people are murdered in a short time, thousands and thousands more starved, degraded, abused, humiliated, tormented in abominable detention facilities," said prosecutor Alan Tieger.

"And the word for those crimes with that intent is genocide."

So far in the history of the ICTY, which was set up in 1995 at the height of the Balkans wars, the tribunal has only recognised as "genocide" the 1995 Srebrenica massacre of 8,000 Bosnian Muslim men and boys.

Six people, including former Bosnian Serb leader Radovan Karadzic, have been found guilty of genocide at Srebrenica -- Europe's worst bloodshed since World War II.

But to the dismay of victims, judges have so far ruled that there was insufficient proof in any of the trials that genocide was committed in seven other municipalities.

Prosecutors on Tuesday also highlighted the abuses meted out on those rounded up and herded into what they called "torture camps".

"Detainees there were held in inhumane and wretched conditions, were viciously beaten on arrival, before being locked into crowded bloodstained rooms, without enough space to lie down on the bare concrete floors," said another prosecutor Arthur Traldi.

Many of the detainees were beaten to death, while soldiers and other Bosnian Serb forces raped the women.

"Muslims and Croat political, professional and intellectual leaders, police and businessmen were particularly targeted for liquidation," said Traldi.

In camps close to Prijedor men were beaten with baseball bats or iron bars, wounded with knives or forced to drink motor oil.

Opened in May 2012, Mladic's trial is now nearing its end, with the defence on Friday due to start three days of closing arguments. A verdict however is not expected until some time next year.