McCann-Erickson has held the account for five years, but the supermarket chain is said to be in the final stages of negotiations with M&C Saatchi over moving the business.
The expected change in agency follows a recent upturn in fortunes at Somerfield Group, which also owns Kwik Save, under John von Spreckelsen, the executive chairman.
Somerfield Group recently announced profits up from £28 million to £30 million and sales at Somerfield's 590 UK stores rose 1.1 per cent. It had experienced initial difficulties following the 1999 merger with Kwik Save, but recently announced a change in strategy to focus on store refits and new products.
McCann's recent activity has been tactically driven work. However, it had created a series of brand campaigns that used the Birds of a Feather star Lesley Joseph, followed by work using the line: "Good food made easy."
M&C Saatchi did not pitch for the business but it is believed to have been talking to Somerfield over the summer.
A Somerfield spokesman said: "Somerfield is talking to M&C Saatchi regarding potential project work. This is not a formal pitch process and Somerfield is not in a position to disclose the nature of any projects. McCann-Erickson is the incumbent creative agency. It is responsible for the current 'good food made easy' campaign."
Media planning and buying for Somefield remains with Universal McCann and Miles Calcraft Briginshaw Duffy continues to handle creative for Kwik Save.
M&C Saatchi refused to comment.