Credit agency Standard & Poor's said it sees no immediate ratings impact on Russian banks from the Cyprus bailout, though imposing capital controls could lead to operational risks for lenders and borrowers.

Cyprus is finalizing capital controls to prevent a run on its banks when they reopen on Thursday after the Mediterranean island state agreed a rescue package with the European Union.

S&P credit analyst Sergey Voronenko said in a report that restrictions on the flow of funds were having only a limited direct impact on rated Russian financial institutions despite their sizable loan exposure to the island.

Russia's central bank reiterated on Wednesday that it did not see systemic risks to the country's banking system emanating from Cyprus should it impose capital controls, though clients might be "inconvenienced."

S&P estimated that as of January 31, cross-border loans to Cyprus-based companies of Russian origin totaled about 23 billion euros ($29.6 billion) - or around 10 percent of the corporate loan books of the three Russian banks it rates - VTB, Gazprombank and Alfa Bank.

VTB has the biggest exposure to the island among Russian banks via its subsidiary Russian Commercial Bank.

S&P said that cash flows related to these loans could be shifted to banks located in other countries.

"However, the imposition of cross-border capital controls and restrictions on money transferring could lead to operational risks both for lenders and borrowers," it said.

Russian banks have said they see a limited impact from the Cypriot banking crisis, with VTB saying its worst-case losses would be tens of million of euros.

Russian officials have expressed concern that Cyprus may keep capital controls for a lengthy period, and have linked their willingness to restructure a 2.5 billion euro bailout loan granted in 2011 to the duration of such restrictions.

($1 = 0.7777 euros)

(Reporting by Katya Golubkova and Oksana Kobzeva; Editing by Megan Davies, John Stonestreet)