The agency selection, which is being handled by Agency Insight, will see the appointment of a second network to work alongside Wieden & Kennedy, which picked up Vodafone's £250 million global account earlier this year.
The search has been sparked by the company's decision to merge all of the Vodafone subsidiary brands into its main brand by the middle of next year. This will mean that Vodafone networks in Spain, Egypt and Portugal, for example, will be renamed under the global Vodafone brand.
Anna Cloke, the head of corporate communications at Vodafone UK, said: "By the middle of next year we will be one brand. We may well need a network. We are talking to networks because we don't want to reinvent the wheel. Right now they are general discussions."
The total global mobile telecommunications business is worth an estimated £580 million worldwide.
It is unclear how the talks will effect WCRS's tenure of the UK account, which it won from BMP DDB at the beginning of the year. Sources say the agency has been handed a "yellow card" by Vodafone, but Cloke said that the company "has no problems with WCRS".
Vodafone uses more than 276 agencies in different international jurisdictions to handle its tactical work. Cloke admitted that if the rationalisation goes forward, the appointment of a single global network would be more cost efficient.
The review will not affect Wieden & Kennedy's status as the agency of record for the Vodafone brand but it is believed that the client is in search of a strong international network that can service the account in all markets, including those in which Wieden & Kennedy does not have an agency. At present, Wieden & Kennedy has offices in Portland, New York, London, Amsterdam and Tokyo.
In May, Vodafone Group announced the appointment of Wieden & Kennedy as its new principal global creative ad agency. The agency has subsequently produced the high-profile "how are you?" campaign, with a £250 million international budget.
David Wheldon of Tempus Partners, which was charged earlier this year with masterminding all of Vodafone's recent agency appointments, did not return Campaign's calls.