The review is a statutory one and the tendering process is expected to start next month.
The account is one of the biggest press buying briefs in the UK and competition between agencies is expected to be fierce.
MediaCom picked up the account in July 2000 after a review of all of COI's buying arrangements.
The press account was previously held by Mediavest, which kept the television buying brief after the review. OMD won the radio buying brief from Carat and Universal McCann retained the cinema buying account.
Although the accounts were originally awarded on a three-year basis with the option to extend for a further two years, it is understood the review has been brought forward by the prospect of a general election, predicted to take place next May. COI is forbidden to advertise in the 90-day period preceding an election.
A spokeswoman for COI said she was unaware of an impending review and said that the buying accounts did not have to go out to tender until 2006.
Separately, reports suggest that COI will be putting its media planning account up for review this autumn. The account is split between PHD, Manning Gottlieb OMD, Mediaedge:cia, ZenithOptimedia, The Ingram Partnership, Naked Communications and Starcom Mediavest.
COI is in the process of conducting a statutory review of its outdoor media planning and buying account, which is currently held by WPP's Portland Outdoor.
Pitches were held last week and a result is expected within the next few days.