The company, which owns brands that include McVitie's Biscuits, Hula Hoops and Jaffa Cakes, has approached agencies to organise chemistry meetings ahead of a pitch.
Starcom currently handles UB's media, having strengthened its relationship with the FMCG company in 2005 when it added the Jacob's Bakery business to its portfolio.
UB's spend is currently focused on its McVities Biscuits and KP Crisps products. Last year, it spent £5 million supporting the McVitie's brands HobNobs, Fruitster, and Mini Digestives and £4 million on the McCoy and Hula Hoops brands, according to Nielsen Media Research.
Publicis, which is Starcom's sister agency and UB's creative agency, is unaffected by the media review.
United Biscuits is now owned by the private equity groups Blackstone and PAI Partners, after they acquired the business for £1.6 billion in late 2006.