The European Commission is expected to announce a heavy fine on Wednesday on Dutch brewer Heineken for operating a price-fixing cartel in the Netherlands.

Three other brewers may also be fined; Dutch beer maker Grolsch, the world's largest beer producer, InBev in Belgium and the privately owned Bavaria, Dutch media reported on Tuesday, citing unnamed sources close to the case.

The European Commission declined to comment on the media reports but the Heineken acknowledged on Tuesday that it was to receive a fine. Bavaria denied the charges.

"Heineken is expecting a fine from the Commission tomorrow," Heineken spokeswoman Veronique Schyns said.

In September 2005, the four companies were formally charged by the European Commission with fixing prices, exchanging confidential information and dividing up the Dutch beer market among themselves between 1994 and 1998. The four brewers controlled 95 percent of the Dutch market, with Heineken claiming half and the three others 15 percent each.

If found guilty, the companies could face fines of up to 10 percent of their total annual turnover. Since Heineken and InBev had been previously accused of participating in illegal cartels, they would risk particularly heavy fines, although the exact amount was not disclosed.

It would be for the third time this year for the European Commission to hand down anti-trust fines against illegal cartel.

Nearly one month after 10 power equipment makers were fined 750million euros (1 billion U.S. dollars) in January, several lift manufacturers were given a combined penalty worth 992 million euros (1.34 billion dollars), the biggest ever imposed by the European Union's anti-trust watchdog for cartel violations.

Shares in Heineken, Grolsch and InBev all dipped Tuesday following media reports of imminent fines.