Donna Cresswell, comms head at Carlsberg UK, sales of whose flagship brand rocketed in Britain last year, said: 'We are in a pitch situation.'
Ketchum handles corporate and trade PR for Carlsberg UK, but its main activity has been football-related work for the flagship brand - sales in multiple off-trade grocers grew by 67 per cent last year, buoyed by Euro 2004.
Cresswell insisted the review was triggered by the firm's purchase of the Holsten brand last year and not related to Ketchum, whose contract is understood to end within weeks. Phipps PR currently promotes Holsten, while Ptarmigan promotes its Tetleys brand.
Carlsberg UK this January pledged an 'all-singing, all-dancing' PR campaign for Holsten to launch 'around April'. The programme is now on hold.
It is yet to be decided whether a single agency will be brought in to handle all corporate and brand PR.
Ketchum's impending switch to Heineken comes amid reports that the brands are among those jostling for a place in UEFA's revamped Champions League sponsorship structure.
Heineken senior comms officer Nicole McNaughton insisted 'no firm appointment' of Ketchum had yet been made. Heineken has said it wants to create a more consistent global brand.