WARSAW (AFP) - Polish authorities has invited new tenders for a 51-percent stake in ENEA, a state-controlled electricity firm that ranks third on Poland's market.

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Swedish energy group Vattenfall owns 18.7 percent of ENEA, a stake it bought in 2008.

Would-be investors have until July 28 to file their bids, the Polish treasury said in a statement.

In 2009, German power giant RWE withdrew its bid for a majority share in ENEA after having been the only candidate.

At the time, RWE said it had decided to drop its non-binding offer because it had decided the deal fell short of market expectations.

The treasury controls 60.43 percent of ENEA, after having sold a total 16.05 percent of the company's capital on the Warsaw Stock Exchange earlier this year.

ENEA is one of four state-owned power companies in Poland and supplies 20 percent of the country's electricity.