It is understood that the agencies will be whittled down to four in a process handled directly by Morrisons.
Campaignlive.co.uk revealed earlier this week that the supermarket is ending its nine-year relationship with DLKW Lowe and has started to approach creative agencies.
DLKW Lowe had retained Morrisons’ £70 million ad account in 2013 after a pitch against M&C Saatchi and Adam & Eve/DDB.
Morrisons has also split with its digital agency of record, Tribal Worldwide, which it appointed in 2013.
The retailer installed David Potts as its new chief executive in March. A number of senior management executives have since left the business, including Nick Collard, the customer marketing and digital director.
MEC handles Morrisons’ media planning and buying.
In April, Campaign reported that Morrisons had postponed a major integrated campaign that was set to be released on 28 March.