Russia's number 2 airline S7, formerly called Sibir, is eyeing a stake on offer in Austrian Airlines, a spokeswoman for the Russian carrier said on Monday.

Austrian state holding company OeIAG is offering its 43 percent share in Austrian, worth around EUR157 million euros (USD$231.8 million), but has said the size of the stake on offer may change. A 25 percent stake must remain under control of Austrian core shareholders.

"We're examining the possibility of taking part in bidding for Austrian. We're interested in this from the point of view of business development as well as its international component," S7 spokeswoman Irina Kolesnikova said.

OeIAG invited potential bidders for Austrian Airlines to notify it of their interest by August 24.

Earlier on Monday, Austrian shares rose nearly 15 percent to 5.69 euros -- the highest level in more than five months -- as possible suitors for the carrier lined up, including a formal announcement of interest from Germany's Lufthansa.

Air France-KLM and Turkish Airlines are also seen as possible matches. Russia's Aeroflot had shown interest but backed out, saying risks would outperform any benefits.

In 2007, S7 flew 5.7 million passengers.