Ladbrokes Coral Group is seeking an agency to work on its consolidated advertising account.
The process is being run through Oystercatchers and chemistry meetings will take place next week.
The selected agency will work on both Ladbrokes and Coral, and be tasked with differentiating the two betting brands. The bookmakers merged in 2016, then online rival GVC Holdings acquired the combined company in a £4bn deal last year, creating one of the world’s largest gambling groups.
Cravens currently handles advertising for Ladbrokes, while Alpha Century works on Coral.
Dominic Grounsell, managing director of GVC UK sports brands, said the company requires a larger creative agency to take on the size and scale of Ladbrokes Coral's new integrated, dual-brand approach.
He added: "We would like to thank both Cravens and Alpha Century for the amazing creative work that they have done in recent years with the Ladbrokes and Coral brands respectively. Both the Ladbrokes and Coral digital businesses have been the fastest-growing brands in the sector in recent years and both agencies have played a significant role in this success.
"We are now looking for one big integrated creative agency to take on both the Ladbrokes and Coral brands in a consolidated approach to drive the next phase of growth for both businesses."
In 2017, Ladbrokes Coral awarded its consolidated £40m media planning and buying business to the7stars, which is not affected by this review.
Last year, Cravens created a Ladbrokes campaign for the Fifa World Cup in Russia featuring celebrities including actor Brian Blessed and model Kelly Brook.
Cravens did not respond to a request for comment and Alpha Century declined to comment.
The gambling industry has been under increasing pressure in terms of advertising. Several brands, including Ladbrokes Coral, Bet365, Betfair, Betfred, Paddy Power, Sky Bet, Stan James and William Hill, agreed to a voluntary live sports ban that went into effect this year.