"The company is making every effort to keep to this schedule," Alexander Medvedev said.
The launch of supplies was previously planned for early 2009.
Sakhalin II includes the Piltun-Astokhskoye and Lunskoye oil and gas fields on Sakhalin Island's northeastern shelf, with recoverable reserves estimated at 150 million tons (1.1 billion bbl) of oil and 500 billion cubic meters of natural gas.
The minority partners in the project, Royal Dutch Shell, Mitsui and Mitsubishi, currently hold 27.5%, 12.5% and 10% stakes in the project respectively. Russian natural gas monopoly Gazprom acquired a controlling stake (50% plus one share) in the project in December 2006.