At a meeting in Belgrade, party officials read a letter by Seselj, who called on party sympathisers from a detention unit of the International Criminal Tribunal for the former Yugoslavia to vote at a coming referendum for Serbia's new constitution so as to prevent the "Kosovosation" of Vojvodina.
The ICTY indictee said in his letter that Serbian President Boris Tadic and Prime Minister Vojislav Kostunica were carrying out the western policy aimed at breaking up Serbia.
Party officials once again called on SRS members and sympathiser to vote at the referendum.
The Serbian parliament last Saturday approved a new constitution, declaring the UN-run province part of Serbia.
The lawmakers -- 242 of them present at the session -- unanimously voted in favor of the constitution, that will replace the current one drafted in 1990 by late former autocratic leader Slobodan Milosevic.
Given that the new constitution needs a yes-vote on a national referendum before becoming valid, the Serbian parliament speaker set the plebiscite for October 28 and 29, urging voters to give the proposed new constitution the legally required two-thirds support and underscore Serbia's opposition to possible independence for Kosovo that might come as the result of the UN-brokered talks on the province.
Kosovo is a province of Serbia but Belgrade has had no authority over the separatist region since a 1999 NATO bombing campaign forced Serb troops to pull out and end a crackdown against ethnic Albanian separatists.