Pitches will take place in February. The company owns brands including Cobra, Carling and Coors Light.
A statement from the company said: "Molson Coors continually reviews its agency partners to ensure it has the best operators to build its portfolio across the globe.
"We can confirm that we are undertaking a review of our below-the-line agency support across the UK but will not comment further while the process is on-going."
In September the brewer retained ZenithOptimedia, the Publicis Groupe agency, to handle its £15 million media planning and buying account following a six-month global review of the business.