The review is being run by Roth Observatory and is, according to one source, in "very early" stages.
In July, Publicis London was handed the FerreroRocher global advertising account after a competitive pitch.
Rainey Kelly Campbell Roalfe/Y&R, Ferrero Rocher’s UK creative agency, was not affected.
Aesop handles Tic Tac’s advertising and recently released an integrated campaign, called "find a fiver", that included TV ads and a consumer competition.
Omnicom Media Group holds Ferrero’s £72 million global media planning and buying business.