A 24-year-old delivery driver has been arrested on suspicion of theft by an employee after more than 120 parcels went missing.
Hampshire and Isle of Wight Constabulary said it was contacted by the managers of Evri last week after a number of jobs in Southampton were not completed.
Officers attended an address in Bassett in the early hours of Monday and arrested a man from the city who remains in custody.
The force said the suspect was a sub-contractor working on behalf of the delivery firm.