The CWU represents 134,000 Royal Mail staff and has been critical of the organisation in the past, most recently when it announced in March that 1,600 jobs are to be axed.
Under the pilot scheme, workers from about 100 offices nationwide will be required to deliver parcels on Sundays from June. There are also plans to make Sunday deliveries within the M25 the norm.
Ward said the union had worked closely with the Royal Mail to “grow the company and improve services for customers”.
“We appreciate that in order to stay competitive in a broadly unregulated sector Royal Mail has to expand its services,” he said. “We believe that offering Sunday delivery and collection services is the right response from the company. With ever-increasing numbers of people opting to shop online, Sunday services are necessary to deal with the growing demand in parcel delivery.”
Ward added that the union is working with the Royal Mail to ensure employees with Sunday shifts will receive “good terms and conditions” and that where possible, the work would be done voluntarily.
Royal Mail chief executive Moya Greene praised the union’s part in putting together the proposals, saying its support has “enabled us to respond quickly to a changing market”.