China National Petroleum Corp may buy up to three billion dollars worth of shares in the initial public offering (IPO) of Russian state-owned oil group Rosneft, press reports said.

CNPC, the country's largest oil group, is one of at least four major foreign energy firms Rosneft is talking to ahead of its IPO that will raise as much as US$11.6 billion (8.75 billion euros), the Financial Times reported.

A file photograph shows the Moscow headquarters of oil company Rosneft. China National Petroleum Corp may buy up to three billion dollars worth of shares in the initial public offering of the Russian state-owned oil group. [AFP]

The oil companies were offered the chance to buy stakes worth between one billion and two billion dollars, the Financial Times said, citing people familiar with the discussions.

CNPC replied to the offer by saying it would like to invest up to three billion dollars, the newspaper reported.

The South China Morning Post newspaper also said CNPC wanted to invest up to three billion dollars in Rosneft but only if it offered something substantial in return about accessing energy resources in Russia.

One of the options put forward by CNPC was an expansion of an existing long-term contract for Rosneft to supply crude oil to CNPC, the Hong Kong newspaper said, citing an unidentified source.

Another reported option was allowing CNPC to take part in the development of Rosneft's Vankor oilfield in eastern Siberia.

"Just investing three billion dollars for a five percent stake is not exciting," the newspaper cited the source as saying. "There has to be something attached to that."

CNPC officials declined to comment on the reports.

A decision on CNPC's possible role must be made quickly if Rosneft is to meet its goal of selling shares in Moscow and London by the middle of the month.

Malaysian national oil company Petronas confirmed on Monday it was considering acquiring a stake Rosneft but did not give any details about its potential investment.

Rosneft's listing has attracted growing controversy because of the company's business background. Its fallen rival Yukos has asked the British markets watchdog to block the IPO because it says Rosneft stole its assets.

China won its first Russian oil industry foothold last month with the purchase by Sinopec, the nation's second biggest oil firm, of a major subsidiary to Russian-British oil group TNK-BP.