Purdie has most recently been running his own CRM consultancy, with Wegener being one of his main clients.
The group said the appointment of Purdie will complement his background in client-side marketing and database consultancy.
Purdie has worked across a number of industry sectors with clients such as Boots, Sainsbury's, Toys R Us, Vodafone, Tesco, News International, Goldfish, Diageo, Lloyds TSB and IBM.
Wegener DM CEO David Perkins said: "It is our aim to provide a service that understands a client's needs and how customer knowledge can drive greater profit growth.
"Rob's appointment and his strengths in both marketing and technology further enhances our ability to offer practical working solutions."
Wegener DM, which has a turnover of £30m in the UK, employs more than 450 staff in eight locations and is part of the €1bn Dutch media company Royal Wegener NV.
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