Russians' trust in Vladimir Putin has dropped to its lowest point since the annexation of Crimea as his unpopular increase in the pension age is signed into law.

Only 58 per cent of Russians said Mr Putin could be trusted, down from 75 per cent last year, according to survey results by the independent Levada Centre published on Thursday. He had the faith of 51 per cent of Russians in 2012, but his ratings skyrocketed after troops seized Russian-speaking Crimea from Ukraine in 2014.

The growing mistrust came as Mr Putin signed a controversial law on Wednesday night that will raise the pension age for men from 60 to 65, just one year below the average male life expectancy here. Women will see their retirement put off from age 55 to 60.

The pension reform sparked protests around Russia this summer by both the liberal opposition and communists normally loyal to the Kremlin. Nine out of 10 Russians opposed the legislation when it was first proposed in June.

Opposition leader Alexei Navalny has been repeatedly jailed since he called his supporters to the streets in dozens of cities in September.