The review originally just included brand advertising but will now take in the retailer's ad accounts for its food, pharmacy and funeral services.
The pitch, which is being handled by the Co-operative's procurement team, will not include its financial services business.
The retailer previously used McCann Erickson to handle its brand advertising account.
To launch the retailer's recent rebranding, the agency produced a two-and-a-half-minute spot accompanied by the Bob Dylan track Blowin' in the Wind.
McCann Erickson announced in July that it was declining to repitch for the business.
The decision to widen the review marks an initiative by the Co-operative Group to appoint a roster of agencies to help develop an overarching brand message across all communications channels.