Pernod Ricard, the French drinks group, faces a potential challenge to its £7.5 billion (€11 billion) offer for Allied Domecq after Constellation Brands of the US confirmed yesterday that it had hired bankers to advise it on a possible rival bid for the UK spirits company.

Constellation said it was evaluating options with "a number of potential partners". With a market capitalisation of $6.1 billion, Constellation is not large enough to buy Allied on its own. But it could mount a counter-bid with partners, which could include other spirits companies or private equity firms.

"It would have to be a joint bid," said Mark Swartzberg, an equity analyst at Legg Mason.

Allied has not signed an exclusive offer with Pernod, which means that it has a fiduciary duty to shareholders to consider offers from other companies.

It is understood that Constellation has not approached Allied with a serious bid, and has not carried out any due diligence work at the spirits company.

Allied's shares rose 8.5 pence yesterday to 671½p, above the 670p that Pernod's initial offer was pitched at. Constellation rose 43 cents to $56.38 in early New York trading.

Allied's shareholders are not due to vote on the Pernod offer until the end of June, and the deal is not scheduled to be completed until July, giving Constellation several months for a counter-bid.

Constellation has told analysts and investors that it would like to strengthen its spirits portfolio by purchasing premium brands. It tried to buy Malibu when the brand was sold by Diageo in the break-up of Seagram, but lost out to Allied.

Constellation has to date focused on its wine business, making a number of big acquisitions. It bought BRL Hardy, Australia's largest wine producer, in 2003 and acquired Robert Mondavi of the US last year.