EU competition chief Margrethe Vestager could send a formal letter of objection to the Russian company on Wednesday, according to the news outlet.
The European Commission started a formal investigation into an alleged breach of competition laws by Gazprom, including Eastern Europe overcharges, in 2012.
Russia supplies about 30 percent of Europe's gas. A number of countries rely heavily on Gazprom for gas supplies.
Gazprom is currently planning to build a new Black Sea pipeline, dubbed the Turkish Stream, capable of delivering up to 63 billion cubic meters of Russian natural gas annually to Europe via Turkey.
The company supplied 161.5 billion cubic meters of gas to European countries in 2013, according to statements.