The vote beginning on Friday is a test of President Vladimir Putin's grip on power across 11 time zones from the Pacific Ocean to the Baltic Sea as the Kremlin faces malaise at home over faltering living standards and dire ties with the West.

At stake is United Russia's super majority in the 450-seat State Duma, which last year helped Putin ease through constitutional reforms that allow him to run for office again and potentially stay in power until 2036.

The vote runs until late Sunday.

Putin, a former KGB officer who turns 69 next month, has not said if he will seek re-election when his current term ends in 2024. He has served as president or prime minister since 1999.

The Kremlin leader's fiercest domestic critic, jailed anti-corruption firebrand Alexei Navalny, hopes a tactical voting campaign led by his team in exile can hurt United Russia's bid to secure a hefty new majority.

The 45-year-old ex-lawyer whose movement was banned as extremist was jailed in March in a case he called trumped up after recovering from a poisoning with a Soviet-style nerve agent.

His allies, who accuse the Kremlin of a sweeping crackdown, have no chance of gaining even a toehold in real politics after they were barred from running for office because of their association with Navalny's network.

The Kremlin denies any politically-driven crackdown and says individuals are prosecuted for breaking the law.

The Communist party led by parliament veteran Gennady Zyuganov, 77, is seen as the ruling party's strongest rival, followed by the LDPR party headed by nationalist Vladimir Zhirinovsky, 75.

Both those parties, like the Just Russia party, back Putin on many key policy matters.

Australian Associated Press