"The Serbian Radical Party, and I'm saying this for the last time, will not form a government without a new election nor will it support a minority government of other parties, just as it will not seek support for its own minority government," Nikolic told reporters in Belgrade.
He was responding to speculations that the Radicals might form a parliamentary majority with the Socialist Party and the Democratic Party of Prime Minister Vojislav Kostunica and then form a new government.
Nikolic said he was ready to step down as parliament speaker the moment 126 out of the 250 members of parliament sign a petition to that effect.
The Democratic Party of President Boris Tadic said on Thursday it would try to renew talks on forming a new democratic government with Kostunica's Democratic Party, which were suspended after the latter party voted for Nikolic as parliament speaker.