The Trust has appointed the AAR, which has started contacting agencies about a brief that will cover visitor marketing and communication with existing members.
Craik Jones Watson Mitchell Voelkel, the incumbent on the membership account, will not repitch. However, it is being retained by the Trust for strategic projects.
The visitor marketing has been handled by small agencies on a project basis.
Berry Darcy, the National Trust's head of membership marketing, confirmed the review was taking place. She said: "We are looking for a different sort of agency to work with us on our segmentation project, which will consolidate both member and visitor marketing. We will continue to work with Craik Jones."
Last year, the Trust embarked on its first foray into DRTV with a 60-second spot by Craik Jones aimed at encouraging people to visit its sites all year round. The ad was themed around a year in the life of the National Trust and illustrated how the organisation's properties can be visited in all seasons.