The company has approached a number of undisclosed agencies and has drawn up a shortlist of four to pitch for the business.
It is understood that United Biscuits' in-house marketing team is handling the review, with brand managers from each of its biscuit and snack brands briefing the agencies before the pitch.
The successful agency will take on responsibility for digital advertising and branding across the company's portfolio of brands, which also includes McVitie's, Skips, Go Ahead, Penguin, Jacob's and KP Nuts.
United Biscuits has used digital advertising in the past, and appointed a roster of three agencies - Wheel Group's Abel & Baker, Oyster Partners and Cordiant's XM London - in 2002.
There have, however, been few digital campaigns of note for United Biscuits brands since Abel & Baker's revamp of the www.hulahoops.com website in 2003.
The search for a digital agency comes shortly after the company redesigned the packaging for a number of its bagged snacks to highlight the fact that it had cut their saturated fat content by 50 per cent.