The telecommunications giant is conducting a search for agencies to pitch for the business through the AAR. The review is at early stages and BT is also assessing its contracts with other media agencies.
BT was previously bound by rules that meant it had to conduct a statutory review of its media accounts via the Official Journal of the European Community. However, these rules are now relaxed and it is able to review media accounts when the need arises.
Grant Millar, BT's head of media, said: "We are going to pitch our press media implementational planning and buying. We believe it is healthy to have regular pitches across all of our marketing services agencies."
An appointment is expected to be made by the end of the year. BT's planning is handled by PHD and its television buying by the Allmond Partnership.
It has no plans to review these accounts in the short term.
Zenith last defended the BT press buying business in 1998 when it was reappointed following a statutory review. On that occasion it beat off competition from Carat and Initiative Media.
In addition to press buying, Zenith was appointed to handle implementational planning and buying for press and radio. PHD focuses on strategic planning which it won four years ago.
BT's creative account is split between Abbott Mead Vickers BBDO, M&C Saatchi and St Luke's. BT said recently that it had no imminent plans to review its creative arrangements.
Simon Marquis, Zenith's chief executive, declined to comment on the review.