The soft-drinks giant has scheduled meetings with existing roster agencies, and has also asked a number of non-roster digital shops to provide credentials.
The process is understood to be procurement-driven.
The review is being led by Joanna Hyder, the head of digital marketing at Coca-Cola, who recently returned from maternity leave.
Although a decision has yet to be made as to the extent of the roster expansion, it is understood that any new agencies that are appointed will be assigned briefs across Coca- Cola's 16-strong portfolio of UK brands, which includes Coca-Cola, Sprite and Oasis.
The company's existing UK digital agencies include glue London, AKQA and Grand Union, as well as the digital start-up Work Club, which was appointed in September last year to develop a pan-European digital strategy for Coca-Cola's sponsorship of this summer's Euro 2008 football tournament.
The process coincides with a review of the global advertising account for Diet Coke, which is currently handled by VCCP in the UK and Publicis Mojo New Zealand globally.
Coca-Cola is also considering reviewing the global ad arrangements for its other Coke brands.