"Today an important step will be made towards implementing our accords. A basic agreement on cooperation between Gazprom and the Hungarian Development Bank will be ready for signing," Putin said during Russian-Hungarian intergovernmental consultations in Moscow.
The South Stream pipeline is designed to pump 31 billion cubic meters per year of Central Asian and Russian gas to the Balkans and on to other European countries, but its capacity could be increased by a further 16 billion cu m. The project involves Bulgaria, Serbia, Hungary, Italy and Greece.
The first deliveries along the South Stream pipeline are scheduled to start in 2013.
Russia and Hungary have also drafted a document on building a gas storage facility in Hungary, the Russian prime minister said.
"A separate document on building a large underground gas storage facility on the territory of Hungary has been drafted. Hungarian company MOL is Gazprom's partner in this project," Putin said.