Consumer Focus found that new PO Locals are providing poor service, charge incorrectly for stamps and are seeking to limit cash withdrawals.
The Post Office is planning to replace one in five post offices with new PO Locals in nearby shops and garages from this summer.
The new branches will stay open for longer than conventional sub-post offices, and cost less to run.
However a ‘mystery shopping’ study of the PO Locals, which have been so far opened at 105 locations across the country, painted a picture of poor customer service.
Consumer Focus found “widespread evidence of inconsistent and often inaccurate product and pricing advice”.