The review of the business is to be handled by intermediary Agency Insights.
A spokesperson for the WWF said that WWAV had worked with the charity for the last three years, but had declined the offer to repitch, and that Agency Insights was now actively involved in searching out agencies to compete for the direct marketing and media brief.
Last week, WWAV lost the £18m consolidated Orange direct marketing account to Harrison Troughton Wunderman.
The agency picked up the business following a four-way shoot-out against Chemistry and the incumbents Craik Jones Watson Mitchell Voelkel.
In its latest promotional activity in March, The World Wildlife Fund added more than 150 of its global conservation projects to online satellite map Google Earth. Users are now able to learn about the location of projects, read a description of each and click through to the charity's website.