UPDATE 2-Spain's Solbes irked by Gazprom's Repsol ambitions

(Adds Repsol chairman comments paragraph 5)

MADRID, Nov 13 (Reuters) - Spain's Economy Minister, Pedro Solbes, expressed reservations on Thursday about Gazprom's GAZP.MM interest in buying 20 percent of oil company Repsol YPF REP.MC, but said any bid would have to be considered seriously.

Russia's Deputy Prime Minister, Alexander Zhukov, said on Wednesday Russian gas export monopoly Gazprom was interested in buying a stake in Repsol held by Spanish builder Sacyr Vallehermoso SVO.MC.

Solbes said a foreign buyer would not be his first choice.

“We’ve privatised companies in Spain, and it grates with me when state-owned foreign companies come and buy them,” Solbes said, but added: “We have to analyse it seriously.”

Separately, Repsol chairman Antonio Brufau said on Thursday the company would welcome new shareholders so long as they did not diminish the growth capacity of Repsol and that the oil firm continued to be “private, independent and Spanish”.

Industry Minister Miguel Sebastian said in September he preferred a Spanish buyer for the stake, which was put on the block by debt-laden Sacyr as it seeks to generate cash in a falling property market to meet its rising financing costs.

Spain has attempted to fend off foreign companies taking stakes in key sectors in the past, causing conflict with the European Commission, which supports the free flow of capital within the EU.

Brussels has accused Spain of breaking European Union law by insisting mergers in its energy sector be pre-approved by the national regulator, such as German utility E.ON's EONG.DE takeover offer for Spanish rival Endesa ELE.MC in 2006, in a move widely seen as an attempt to block foreign predators.

Some analysts have said the sale of the stake could lead to a full-scale takeover or break-up of Repsol, which has lagged rivals in profitability and in reserves growth in recent years.

Russia has tacitly encouraged its energy companies to make acquisitions abroad, and Gazprom is expanding its foreign portfolio, though debts of $40 billion could limit its ambitions. (Additional reporting by Carlos Ruano) (Reporting by Andrew Hay; writing by Sonya Dowsett, Editing by Will Waterman and Andrew Macdonald)