The appointment sees MPG reunited with the Tories ahead of a probable General Election in 2009 and the impending London Mayoral Elections.
MPG was responsible for the Tories' media at the last election, but the party hired PHD in October 2007 when the prospect of a snap election being called seemed likely. However, PHD was not retained.
Newspaper sources said MPG had been in contact to book campaigns in the coming months. In addition to traditional media, the Tories are turning to online campaigns.
MPG's appointment follows the selection of its sister Havas ad agency Euro RSCG London. It created a campaign with the line "Bottler Brown - zero strength" on beer bottles, taunting prime minister Gordon Brown over his decision not to call an election.
MPG declined to comment.