The record company is understood to have approached a number of agencies with a brief document.
It is unclear how this will impact on its current media agency relationships, which are handled locally. Warner Music Group's UK media account is held by ZenithOptimedia, but the music company is understood to use other agencies in local markets across Europe.
The media for Warner Bros Studios is handled separately, with PHD working on the UK business.
A tie-up of digital media across Warner Music Group and Warner Bros Studios into one agency is unlikely, although Omnicom, Group M and Publicis agencies are understood to have been approached by the music group.
Warner Music Group's roster of international artists includes Fleetwood Mac, Muse and REM.
The music company was unavailable for comment.