Bell Pottinger Public Relations, Jackie Cooper PR and Ketchum are set to share an annual PR spend that industry sources believe to be in excess of £3m per year.
Masterfoods head of external affairs Michael Jenkins said the four-month review, which ended last week, was held to assess agencies' 'creativity, proactivity and capacity'.
Jenkins confirmed that the other two agencies on the roster, Freud Communications and Jane Stevenson PR - which work on Celebrations and Lockets respectively - will cease work when their contracts expire in early 2003.
Bell Pottinger and JCPR - which have worked for a selection of Masterfoods brands in the past - will begin work on their enhanced portfolios from the start of next year. Ketchum - which has worked for Pedigree Masterfoods for six years - will continue to work on petcare and food products.
Masterfoods was formed in January this year by the merger of Mars Confectionery and Pedigree Masterfoods. The company is a subsidiary of Mars UK, which is owned by the privately-held US giant Mars Inc.
In the UK, confectionery is produced at a plant in Slough, Berkshire.
Earlier this year Masterfoods relaunched its flagship Mars bar with the slogan 'Pleasure You Can't Measure'. This replaced the classic 'A Mars A Day Helps You Work Rest And Play' catch-line in a change reported to have cost more than £7m.
In late 2001, Mars ended its 40-year relationship with ad agency D'Arcy, switching pan-European work to Grey Worldwide.