The government agency, which has merged its buying contracts with the Department for Transport, said a re-tender of the television and radio contracts would begin this month.
The accounts, currently held by Starcom Mediavest and OMD respectively, were last reviewed in 2000 and a result is expected by March.
COI said the press contract, held by Mediacom, and cinema, held by Universal McCann, will be re-tendered in March 2005.
COI also plans to re-pitch the strategic media-planning roster in July 2005.
The outdoor buying contract was reviewed earlier this year, with Posterscope appointed.
COI said the online planning and buying account, held by I-Level, would not be affected.