(Adds details, company comment)
ZURICH, Nov 11 (Reuters) - As Russian and Swiss billionaires fight for control of Schmolz & Bickenbach, the embattled Swiss steelmaker on Monday rejigged proposed terms for its planned capital increase ahead of an extraordinary shareholders meeting.
Schmolz & Bickenbach will now ask its shareholders on Dec. 2 for permission to raise up to 614.25 million Swiss francs ($616.16 million), more than its original proposal to raise 189 million to 350 million francs.
The company, which has been wrestling with falling demand for steel, said raising the limit is a "technical necessity" to help ensure it meets its minimum fundraising target of 325 million francs.
The move comes as Swiss billionaire Martin Haefner seeks to buy up to 37.5% of the company, up from 17.5% at present, and the investment vehicle of Russian oligarch Viktor Vekselberg, now with a nearly 27% stake, separately tries to remove the steelmaker's board of directors.
Haefner's BigPoint Holding has offered to commit 325 million francs, on the condition that after the capital increase its stake came to least 37.5%.
The arrangement would put the Swiss car dealership billionaire at the controls of Schmolz & Bickenbach after he demanded Vekselberg's Liwet Holding be allowed to increase its holding only in line with its existing stake and be blocked from buying additional shares created and offered to the market.
"We are working towards the conditions that Mr. Haefner has set, but we have to treat all shareholders equally and fairly," said Schmolz & Bickenbach spokesman Ulrich Steiner, of the raised limit.
"This increases the transaction probability if (Haefner's) 37.5% condition does not materialise because the other shareholders exercise all their subscription rights."
The money raised will be used to support the company's balance sheet, after it posted three profit warnings this year.
Schmolz & Bickenbach, which makes precision, acid and heat-resistant steel, is due on Tuesday to report its third quarter results where analysts expect a loss of 51 million francs.
In addition to the Dec. 2 EGM to decide the capital increase, a separate, still-to-be-scheduled shareholder meeting would decide on Liwet's proposal to remove Schmolz & Bickenbach's board of directors. ($1 = 0.9969 Swiss francs) (Reporting by John Revill, editing by John Miller)