UK brewer Scottish & Newcastle has rejected an improved 780p-per-share bid proposal from Carlsberg and Heineken.
S&N's famous brands include Newcastle Brown Ale
However, S&N said it would be willing to talk to the firms about a bid of at least 800p per share.
S&N, whose brands include Newcastle Brown Ale and Foster's, had previously rejected an offer of 750p per share.
Carlsberg said that the consortium would not make a hostile bid and called on S&N shareholders to support the improved proposal.
The UK Takeover Panel has given the Carlsberg-Heineken consortium a deadline of 1200 GMT on 21 January to make a formal bid.
If Carlsberg and Heineken are successful in buying S&N, their plan is to split the company up.
Heineken would take control of S&N's main business in the UK and some other European markets, while Carlsberg would take over the operations in France and Greece.
Carlsberg would also gain full control of Russia-based brewer Baltic Beverages Holdings (BBH), which is currently jointly owned by it and S&N.
However, S&N says that by making the bid with Heineken, Carlsberg has breached the terms of the BBH joint agreement.
As a result, it has submitted a claim to an arbitration panel arguing it should be allowed to buy Carlsberg's 50% stake in the venture.
S&N said that it would be prepared to talk to the Carlsberg-Heineken consortium if it made a firm proposal of at least 800p per share and once Carlsberg had agreed to the publication of "proper information" about BBH's prospects.
In a statement, the consortium said that the 780p-per-share offer represented "a value which is significantly in excess of the standalone value of S&N".
It also said that it had put forward proposals to provide the market with more information about the financial prospects for BBH from 2008-2010.
"It is decision time for S&N shareholders," said Jean-Francois van Boxmeer, Heineken chief executive.
"Without the S&N board's co-operation, there will be no offer by the consortium."