A member of a local electoral commission wearing a protective face mask gives a ballot to a voter to vote in regional polls.

Russians on Sunday vote in regional polls overshadowed by the poisoning of main opposition leader Alexei Navalny, an economic crisis exacerbated by the coronavirus and major protests in some regions.

In 41 of the country's regions, Russians are voting for regional governors and assemblies as well as in four by-elections for national MPs and other polls.

Coming a year ahead of parliamentary elections, the vote will be seen as a key test of the Kremlin's electoral machine amid simmering public anger over falling incomes and economic trouble.

Tatyana Stanovaya, head of the R.Politik analysis firm, said the results of the polls will help the Kremlin determine whether the unpopular ruling party United Russia needs to be reformed and if parliamentary elections should be pushed forward.

Navalny's poisoning could also influence voters and bring about "contradictory effects," Stanovaya said.

After he was evacuated from Siberia to Berlin, German doctors said Navalny had been poisoned with a Novichok nerve agent.

His associates believe the use of the banned chemical weapon shows only the Russian state could be responsible.

With Navalny in a German hospital and absent from Russia's political scene, the "smart voting" campaign he had launched may be undermined, Stanovaya said.

Led by Navalny, the opposition hopes to challenge Kremlin domination over Russia's political life by promoting tactical voting, urging Russians to back the strongest candidate on the ballot to defeat the ruling party.

A woman walks to cast her ballot to vote in regional polls at a polling station in Novosibirsk.

"On the other hand, what happened to Navalny caused a shock," Stanovaya added, noting that some of those who did not support him in the past may now change their minds.

President Vladimir Putin's top foe had been in Siberia to promote "smart voting" when he fell ill.

Three-day polls

With United Russia facing a deep popularity crisis, elections in the country are for the first time being held over three days and some polling stations will be open-air.

Early voting began on Friday and the main polling day is on Sunday.

The controversial three-day voting scheme was first tested this summer, when a national vote on constitutional amendments that made it possible for Putin to stay in power until 2036 was also held over multiple days.

At the time the Kremlin pulled out all the stops to bolster the turnout and makeshift polling stations -- often ridiculed on social media -- cropped up across the country, including in buses, tents and on street benches.

The measures were officially introduced to guard against coronavirus, but the opposition accused the vote organisers of mass vote-rigging.

In what some observers believe is another Kremlin ploy to dilute the opposition vote, candidates are also standing for four little-known new parties.

A man casts his ballot at a polling station in Novosibirsk.

Saying no to the regime

One of the highest-profile campaigns has taken place in Novosibirsk, where the head of Navalny's office in Russia's third largest city, Sergei Boiko, brought together the opposition to counter United Russia and the Communist Party.

His "Novosibirsk 2020" coalition has put forward around 30 candidates for the city legislature and campaigned with the help of volunteers from Navalny's Anti-Corruption Fund.

"This is an attempt to unite the opposition, all the people who are saying 'no' to the current regime," Boiko told.

In a final push before the polls, Navalny's team urged Russians to vote the ruling party out of power.

"Any deputy is better than a member of United Russia," the team said.

"Elections can be won," it added, pointing to the far eastern city of Khabarovsk.

Tens of thousands have taken to the streets there for the past two months over the arrest of a governor who defeated an incumbent from the ruling party in 2018.

The case of the former Khabarovsk governor and the protest movement in Russia's neighbour Belarus have both sparked small-scale demonstrations in solidarity in Russian cities, suggesting there is growing potential for a protest vote.