The review is being handled by Ingenuity.
It comes as KP Snacks is set to appoint Jeff Swan, the former Cadbury marketing director, as its marketing chief. Swan will replace George Johnston, KP Snacks’s current director of marketing.
Last year Crispin Porter & Bogusky created an ad called "McCoy's ultimate" for the brand, on a project basis.
KP Snacks awarded its £10 million UK advertising account to BMB in September 2013 following a pitch handled through Ingenuity. However, BMB is understood to have not worked on the McCoy’s brand.
A spokeswoman for McCoy’s declined to comment.