Viktor Zubkov, Russia's deputy prime minister and head of the Gazprom board of directors, described the pending agreement as "the last in a series of organizational documents" needed to start building the pipeline through the Balkans, Russia's RIA Novosti reports.
Russia aims to diversify its transit options to Europe with South Stream. The project is designed to carry as much as 2.2 trillion cubic feet of natural gas each year through the Balkans and on to southern Europe.
Zubkov visits Budapest on Jan. 29 to sign an agreement to create a joint venture for the Hungarian section of South Stream. He said construction for the pipeline could start at the end of 2010.
The route for South Stream remains unsettled, however, as officials in Serbia bicker over the route for the 280-mile South Stream leg through their country.
Gazprom last week established a special project management department to oversee developments of the South Stream. Deliveries through the pipeline are expected by 2015.