The All-Russia People's Front is a "rebranding" of the ruling United Russia party, A Just Russia party leader Sergei Mironov said on Tuesday.
"This is an attempt to camouflage United Russia as a bloc of 'party and non-party people,'" he said.
"To ensure the bloc's victory, regional leadership... is being hastily replaced with people loyal to the ruling establishment."
Mironov, who lost his job as speaker of the upper house of parliament last month, was elected leader of the party faction in the lower house.
The solution to Russia's problems is not in "pushing people into all sorts of fronts," but in abolishing the one-party monopoly, he said.
Neither United Russia nor People's Front officials have yet commented on Mironov's remarks.
He vowed last Tuesday to keep up his critical stance on the ruling party - which resulted in his exit from the Federation Council - from his new position in the State Duma.
St. Petersburg's legislative assembly, which had nominated Mironov to the Federation Council, voted to recall him on May 18 after he came under fire from the ruling United Russia party for his criticism of St. Petersburg Governor Valentina Matviyenko, who later in the day plans to meet with President Dmitry Medvedev to discuss the offer of assuming the post of speaker of the Federation Council, thus replacing Mironov.
Analysts say Prime Minister Vladimir Putin is concerned that his United Russia party could struggle in the elections, suggesting his creation of the All-Russia People's Front is a bid to head off a potentially damaging poor showing by United Russia.
Putin announced the formation of the People's Front in early May, saying it would broaden United Russia's electoral base with "non-party people," including trade unions, NGOs, business associations and youth groups.
Mironov's break with the Kremlin is seen by some analysts as a move to cast him as an opposition figure who might subsequently head a "controlled opposition" to lend greater legitimacy to next year's presidential elections.