Russian energy giant OAO Gazprom (GAZP.RS) and Hungary signed a final shareholders' agreement to build the Hungarian section of natural gas pipeline South Stream, Hungary's state-owned power company MVM Zrt. said Wednesday.

The South Stream gas pipeline project will link Russia with Austria by transporting gas across the Black Sea and through Bulgaria, Serbia, Hungary and Slovenia.

The capacity of the 229-kilometer Hungarian stretch, with costs estimated at 600 billion euros ($780 billion), will be 30 billion cubic meters a year. The section is planned to start operating as of Jan. 1, 2016.

Hungary is highly dependent on Russia for its natural gas; the only country where it imports gas from. In 2011 the Russian gas supply to Hungary totaled 6.26 billion cubic meters.

Gazprom Deputy Chairman Alexander Medvedev said at the press briefing that there's a possibility of building a sub-stretch to Croatia, but that wouldn't be a transit route.