The amount of mail sent by consumers has more than halved in the past six years, but internet shopping has fuelled an increase in the number of packets and parcels being delivered, according to a new study.
Research by postal regulator Ofcom also showed support for a single class of delivery, less expensive than first class and delivered in two days.
A survey of 4,000 residential consumers showed the average number of items sent each week has fallen from around 3.5 to 1.5, with the trend expected to continue in the coming years.
More than a third of residents received a packet or parcel at least once a month, up from 27% in 2010, and half predict they will order more goods on the internet.
A separate poll of 1,100 businesses showed that two thirds of mail they sent was first class.
Most of the residents and businesses said greetings cards, packets and parcels will always have to be sent by post, while virtually everyone described the level of service as acceptable.
Suggested improvements to Royal Mail's parcel delivery service included changes to office opening times, improved tracking services, and the ability to choose a delivery time-slot.
Billy Hayes, general secretary of the Communication Workers Union, said: "This research clearly shows the value that people put on the post and highlights growth areas for consumers who predict they will increasingly rely on postal services for the delivery of parcels and online purchases.
"We want to see innovation, not cuts, in order to maintain and improve service standards."