The number of Russians who regret the break-up of the Soviet Union has risen to its highest since 2005, amid rising economic concerns and nostalgia for the Soviet welfare system, the Levada pollster said on Wednesday.

President Vladimir Putin famously dubbed the 1991 dissolution of the Soviet Union the greatest catastrophe of the 20th century and he and many Russians have long lamented the blow its demise dealt to Moscow's great power status.

The number of Russians pining for the Soviet past has been steadily rising under Putin since he returned to the presidency in 2012, poll data issued by the independent Levada Center on Wednesday showed.