The centralisation follows Morrisons' takeover of the Safeway chain - MEC Manchester was previously Morrisons' agency of record, while Manning Gottlieb OMD handled Safeway.
Later this year, Morrisons will be undertaking a rebranding of its 430 Safeway stores. It has started advertising its price-led approach in the national press using the "Enjoy the change" logo.
The ads announce there will be thousands of permanent price cuts over the summer.
No decision has been made on the creative account, although the Manchester-based BDH\TBWA is widely expected to emerge triumphant. BDH is Morrisons' agency, while Clemmow Hornby Inge handles the Safeway brief.
Following approval of the takeover earlier this year, Morrisons has downsized the southern head office of Safeway and has returned the marketing department to its headquarters in Bradford.
The Morrisons marketing services director, Michael Bates, has taken on a group role with control of Safeway's marketing department. He is overseeing the rebranding of Safeway stores to Morrisons.
The first Safeway to be converted to a Morrisons outlet was in Ripon, ahead of the national conversion programme beginning in August. The biggest stores will be known as Morrisons, while mid-sized shops will be renamed Morrisons Choice. The smallest stores will be called Safeway Compact.