The decision means MPG will take control of all media activities across Europe, the Middle East and Africa, in addition to some markets in Asia and Latin America.
It is believed that Interpublic network Initiative will continue to handle the estimated £500m consolidated Hyundai Kia business in the US and Australia.
The car group's media business in its domestic Korean market is not believed to be affected by the review.
From January, MPG will handle a newly consolidated account that includes the £30m media business in the UK, currently split with Omnicom's M2M holding the £18m Kia account and ZenithOptimedia's Equinox holding the £12m Hyundai business (based on spend to 30 April tracked by The Nielsen Company).
MPG and Havas declined to comment, referring calls to the client.
A Kia spokesman confirmed a decision has been made and a group announcement is due on Monday (9 November).
The global review process was handled by Innocean, the in-house marketing services department at Hyundai Kia, led from the head office in South Korea.