The review is said to be statutory and is believed to part of a European review conducted market-by-market across the region.
The chewing gum manufacturer, which is understood to have informed its incumbent agencies across Europe about the review, has an annual media budget in UK of £12.7m, according to Nielsen Media Research.
Wrigley's products include the Wrigley's Spearmint and Doublemint gum, Airwaves, Juicy Fruit and Hubba Bubba brands.
A spokeswoman for Wrigley's said: "This is a statutory review of the media planning and buying business and we have been happy with the service that MediaCom has provided for us during its time on the business."
In January, Wrigley's awarded its $150m (£85m) US media planning and buying account to WPP Group agency MindShare after a pitch against fellow Wrigley's roster agencies OMD and sister WPP agency MediaCom.
MediaCom has held the Wrigley's media account in the UK since 2002, when it won the account from incumbent Mediaedge:cia in a final battle against Starcom.
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