Opinion pollsters have predicted that the SPS will receive about 3% of the vote at the State Duma elections. Under the new election laws, parties have to overcome a 7% barrier to make it into the lower house of parliament.
"On average, we garnered 8% at the [local] elections in March," Belykh told a news conference in Moscow on Monday. He added that opinion surveys held a week before the elections had also suggested that the SPS would only gather 2-3% of the vote.
The SPS took part in the weekend's anti-Putin demonstrations in Russia, with one of its top members, Boris Nemstov, briefly detained by police in St Petersburg on Sunday.
Opinion polls
Only one political party - the pro-Kremlin United Russia - will get enough votes to take seats in the State Duma, said Valery Fyodorov, the head of the government-backed VTsIOM pollster, citing a survey conducted on November 17-18.
He predicted that United Russia would win 55.6% of the vote. The other parties close to crossing the 7% margin are the Communists with 5.8%, the A Just Russia party with 4.9%, and the ultra-nationalist LDPR with 4.8%.
"The other parties will get around 1% or less," Fyodorov told a news conference in Moscow.
Pollster forecasts
Meanwhile, VTsIOM experts published their own forecasts on the December 2 elections on Monday, predicting that only four parties would overcome the 7% barrier - United Russia (62.1%), the Communists (12.2%), LDPR (8%), and A Just Russia (7%).
The remaining parties are predicted to receive less than 3% of the vote.
Turnout at Sunday's polls is expected to be around 54%.