The 17,000-strong branch network will maximise customer revenues by giving staff in-depth knowledge of the Post Office's expansion into financial and travel-related products. Some 66,000 people work at Post Office Counters.
The initiative will show staff how to explain the benefits of Post Office-branded products, which include commission-free foreign currency exchange and instant travel insurance.
It follows the announcement of a £194m loss for the Post Office last year at a time when the network is under pressure from the government's decision to automate benefit payments. Under plans announced last month by Royal Mail Group chairman Allan Leighton, the Post Office is to offer a broader range of financial products, including unsecured loans and a credit card.
Beginning with personal loans this October, Leighton wants Post Office branches to generate £200m from sales of financial services products within five years.
The diversification is led by the chief executive of the Post Office, former HSBC marketer David Mills, and sales and marketing director Gordon Steele.
It is designed to exploit awareness of, and trust in, the Post Office brand.
It will also include the ongoing segmentation of the branch network to provide different combinations of products and services according to customer needs. Insiders say that may involve the creation of brand symbols to identify the nature of individual branches to consumers.
The overhaul will be backed by an ad campaign next year emphasising the diversity of the offer. It is likely to use frontline staff to promote the branches as customer-focused and accessible outlets for buying essential services.
Separately, commercial marketing chief Simon Carter is undertaking a review of the Post Office's presence in the domestic telephony market.