The decision follows a rethink of its worldwide marketing strategy (Marketing, 23 July). The global Diet Coke ad account is held by Publicis Mojo New Zealand, while that in the UK is serviced by VCCP, which created its recent 'hunk' campaign.
It is predicted that the global accounts for Coca-Cola and Coke Zero, currently handled by Wieden & Kennedy Amsterdam, will also be put up for pitch.
The company recently used Argentinian agency Santo for its global Pemberton campaign, in which it highlighted the brand's heritage.
This month, chief executive Muhtar Kent said it will 'optimise the use of agencies to reduce costs'.
Coca-Cola, which also works with Mother and Santo London in the UK, denied that a review was taking place.