No details are being disclosed of the project assigned to M&C Saatchi, whose Sydney office already has a relationship with Vodafone.
The London agency has had a gap in its client portfolio since September 2001 when BT transferred its £14 million business account to St Luke's without a pitch.
The switch marked the end of M&C Saatchi's "You can" work for BT, which had run for the previous two years.
JWT was appointed as Vodafone's global agency network in May 2002 with the task of providing the strategy and advertising materials for the company's global brand campaigns. W&K, hired by Vodafone in May 2001, was retained as its global creative agency. At the time, Vodafone announced that the 20 agencies that worked on its business would be phased out in favour of JWT in all of its markets.
Vodafone this week confirmed the appointment of M&C Saatchi to work on a project, but denied it would affect its relationships with JWT and W&K.
David Haines, Vodafone's global brand director, said the decision should not be seen as a big surprise, given that it already worked with M&C Saatchi in Australia.
However, M&C has a track record of using project assignments to make successful inroads into the main account.
Its most notable success was with Sainsbury's, when the agency used the award of an internal communication project as an opportunity to show the supermarket how it might consider projecting its image to consumers. As a result, Sainsbury's switched its television account out of Abbott Mead Vickers BBDO. But M&C Saatchi's tenure of the business was short-lived. It was returned to AMV a few months later.