Walker Media, The Health Lottery’s previous agency, is thought to have resigned the business last year.
It is understood that the account has moved without a pitch into the WPP media shop, which already works with the lottery’s parent company, Northern & Shell.
Since its £20 million launch, The Health Lottery has used sister media owners, such as the Daily Express and Channel 5, for much of its marketing.
Last month, Richard Desmond, the chairman of Northern & Shell, took out an ad in his newspapers to confirm tickets for The Health Lottery will continue to be £1, after The National Lottery announced a ticket price rise.
In July 2012, The Health Lottery hired McCann Manchester to help grow the brand by developing creative work for TV and press under the strapline: "Share the love."
Walker Media was appointed to handle the lottery’s creative and media business in 2011, ahead of its launch.
A spokeswoman for The Health Lottery declined to comment.