The chairman of the BORS association of demobilised soldiers, Pantelija Curguz, said in Banja Luka that rallies in protest against Mladic's apprehension would be organised on Sunday in Kalinovik, Mladic's home village located 60 kilometres southeast of Sarajevo.
The association is planning to organise the main protest rally in Banja Luka on Tuesday, 31 May.
Another BORS official, Drazen Prendija, said that former Bosnian Serb soldiers were embittered by developments.
They accused the Serbian government, including President Boris Tadic, of pursuing a treacherous policy which they said would bring no good to the Serbian political elites.
On Thursday, when Mladic was arrested in Serbia, a representative of former Bosnian Serb prisoners of war, Branislav Dukic, expressed disappointment at his apprehension.
A majority of Bosnian Serb politicians have so far commented on those developments cautiously and with reservation.
The entity's president Milorad Dodik said in a written statement that the arrest was an act of fulfilling the international obligations stemming from the Dayton peace agreement signed by Bosnia and its neighbours.
Reports by the media in that half of Bosnia about the Mladic arrest mainly suggested that he was an innocent man or even hero.
The 69-year-old Mladic is charged by the International Criminal Tribunal for the former Yugoslavia (ICTY) with genocide and other war crimes committed against Bosnian Muslim and Croats during the war in Bosnia and Herzegovina.
The indictment alleges that genocide was committed against the Bosnian Muslim population in Srebrenica, Prijedort, Kljuc, Kotor Varos, and Sanski Most and other areas with the aim of ethnically cleansing eastern and northwestern Bosnian of non-Serbs.
According to the ICTY indictment, apart from Mladic other Bosnian Serb generals were also part of the joint criminal enterprise, including Momir Talic, Stanislav Galic, Dragomir Milosevic, Radislav Krstic and political leaders Radovan Karadzic, Momcilo Krajisnik, Biljana Plavsic and former Yugoslav president Slobodan Milosevic.
Apart from the ICTY, which indicted Mladic for genocide and other war crimes in Bosnia, the Croatian judiciary also wants Mladic for war crimes Yugoslav People's Army (JNA) troops under his command committed at the start of the Homeland War in Croatia in 1991.
A warrant for his arrest is still posted on the website of Croatia's Justice Ministry for war crimes the troops under his command perpetrated against civilians in Kijevo near Knin, Skabrnja and in other villages in the Zadar and Sibenik hinterland.
In 1992, the district court in Sibenik sentenced Mladic and other six people in absentia to 20 years in prison for war crimes against civilians in Kijevo and Vrlika and for the shelling of Sinj and Sibenik and their surroundings. In 1995 Croatian prosecutors pressed charges against Mladic and another three fugitives for having destroyed a dam and hydro-power plant at Peruca with the aim of flooding areas in the Cetina river valley, including Sinj, Trilj and Omis.