MOSCOW, Sept. 22 - Russia faces years of stagnation because of the Ukraine crisis and is ducking decisions needed to achieve a new economic model, former finance minister Alexei Kudrin told the Reuters Russia Investment Summit on Monday.

Kudrin, a long-time ally of Russian President Vladimir Putin, is one of the weightiest figures questioning government policy at a time when Russia is feeling the economic chill from confrontation with the West over Ukraine.

A leading 'liberal', he shepherded Russia's finances for over a decade before resigning in 2011 in a row over rising government spending.