Oct 28 (Reuters) - SPB Exchange, Russia's second-largest bourse, said on Friday it had delayed plans to open up partial trading in some foreign shares, originally scheduled to restart on Oct. 31.

The exchange, which specialises in giving Russian retail investors access to trade hundreds of foreign blue-chip companies, said earlier this week it had reached a deal with an unnamed investor that would allow $312 million of frozen holdings to be traded once again.

In a statement issued on Friday evening, SPB Exchange said it would have to delay the move "for a few days" following consultations with the Russian central bank and brokers.

The extra time would allow for the "reconciliation of balances" and "distribution of securities among clients," it added.

SPB Exchange did not set a new date for the completion of the technical steps that would then allow trading to be resumed.

Russia's central bank imposed some restrictions on trading foreign shares in May after the West imposed sweeping sanctions against Moscow over its actions in Ukraine.

SPB Exchange resumed full trading in a number of foreign equities in August, and the latest move was set to be the next phase of reopening for the platform. (Reporting by Reuters, Editing by Louise Heavens)