The company is reviewing all of its creative, digital and media businesses.
The incumbent agencies, Mustoes and Starcom Motive, have been asked to repitch.
Kia Cars UK underwent an assessment of its suppliers following the company's acquisition by the Korean-based Kia Motors Corporation. The Korean parent acquired the UK operation last October.
At the time, the company characterised the move as an effective rubber-stamping by the new management, with relationships highly likely to remain unchanged.
But it is understood that since that time, the management at the Korean parent company has exerted an increasing amount of control over UK marketing.
Traditionally, Kia has ploughed the majority of its above-the-line spend into TV for brand-building campaigns, while individual marques have mainly been supported with press activity.
Kia is also the brand behind the unusual "think before you drive" campaign, which aims to encourage people to leave their cars at home and use other means of transport for short journeys.
The "think before you drive" campaign, which was launched at the end of 2000, included a two-year sponsorship of "Walking the way to health", a lottery-funded programme run by the British Heart Foundation and the Countryside Agency.
Last October, Paul Williams, the sales and marketing director of Mitsubishi Motors (UK), was appointed managing director of Kia Motors in the UK.