MOSCOW - The head of the Russian deposit insurance agency head said on Friday the share of non-performing loans may climb to 20 percent by the end of 2009 -- the gloomiest forecast from officials to-date.

According to our forecast, the share of overdue loans may rise to up to 20 percent ... We hope there will be no massive defaults, Alexander Turbanov told Ekho Moskvy radio station on Friday.

That figure is twice as high as the central bank's conservative forecast of 10-12 percent. If its forecasts are proved right, the central bank expects Russia's banks will need at least 500 billion roubles ($15.72 billion) of extra capital [ID:nLK352548].

Standard & Poor's said on Tuesday problem loans could soar to 35-50 percent of total lending in Russia, Ukraine and Kazakhstan, though actual loan losses will be no more than half that level in Russia [ID:nLJ957879].

For a factbox on banks' non-performing loan exposure, see [ID:nLL970208] ($1=31.80 Roubles)

(Reporting by Oksana Kobzeva, writing by Dmitry Sergeyev; Editing by Jon Loades-Carter)