The contract will consolidate the charity's existing digital acquisition marketing into one account.
ActionAid currently works with Minute Steak (part of Steak), Online Media Group, TradeDoubler and Affiliate Future.
We Are Social, which works on social media projects for the charity, is not affected by the review.
The charity will experiment with digital in 2011, before the launch of its five-year strategy in 2012.
ActionAid will be holding an open house on Thursday (7 October) for agencies to ask questions about the tender.
The deadline for first stage tender documentation submissions is 15 October.