The supermarket has been with Abbott Mead Vickers BBDO for 35 years. The Omnicom agency last defended the business in 2005 when it beat WPP’s J Walter Thompson to keep hold of the account.
Sources said Sainsbury’s was holding meetings with rival agencies this week in a process being handled by AAR.
A final decision on whether to review could be delayed until after the Competition and Markets Authority's inquiry into Sainsbury's £1.4 billion deal to buy Argos from Home Retail Group. The CMA has until 25 July to decide whether to launch a full probe.
A Sainsbury’s spokeswoman said: "Sainsbury’s and AMV have a well-established relationship that stretches back over 35 years and, as you would expect, from time to time it’s important for us both to take a fresh look."
Sainsbury's retained PHD on its £60 million media planning and buying business in February last year after a competitive pitch involving WPP agencies Maxus and MediaCom, and Publicis Groupe's ZenithOptimedia.
Abbott Mead Vickers, as it was then known, won the Sainsbury’s account in 1981. Its high-profile work for the brand has included a series of ads featuring celebrities such as Dawn French creating their favourite meals in the 1990s and the long-running campaign featuring Jamie Oliver.
In recent years Sainsbury’s has created big-budget ads for Christmas including 2013’s "Christmas in a day", 2014’s "Christmas is for sharing" spot featuring the 1914 Christmas football match in the trenches and last year’s "Mog’s Christmas calamity" featuring the Judith Kerr cat.
There has been a lot of movement in the retail sector this year. In April Asda made the shock move of appointing Publicis Groupe’s Saatchi & Saatchi and Blue 449 to its creative and media accounts without a pitch.
Last month Marks & Spencer called a review of its creative business. Marks & Spencer’s 16-year incumbent Rainey Kelly Campbell Roafe/Y&R is going up against its sister WPP agencies in the pitch.
Update: The original version of this story stated the advertising pitch had started because Sainsbury's provided an inaccurate statement to Campaign.