The postal regulator yesterday launched an inquiry into complaints that letters are being collected from post boxes as early as 9am.
Residents in areas including South Wales, Derbyshire and Ipswich complained that collections are being made before their post was delivered, giving them no time to respond to correspondence on the same day.
Postcomm announced a three-month consultation to check details of when post was being collected and delivered before deciding whether to order any changes.
Chief executive Sarah Chambers said 9am seemed "very early" to be collecting post, adding: "There may be some parts of the country where post boxes are so remote that the only way the Royal Mail can guarantee next-day delivery is to collect post early.
"But we need to find out what customers want. We are beginning to hear some concerns about changes to delivery and collection times.
"People are telling us that in some areas post is being collected as early as 9am, whereas deliveries come later than that.
"We need to find out what customers really want from their post and then we will decide if anything needs to be done about it."
Ms Chambers said collection times seemed to be changing "gradually" in some parts of the country.
Meanwhile, the Royal Mail was warned yesterday that abolishing the limit on junk mail deliveries to people's homes will damage the environment and cost council tax payers more.
The Local Government Association (LGA) has warned that a deal struck by the Royal Mail to lift the three-items-per-week limit of unaddressed mailings will lead to an increase in unwanted deliveries.
Sandy Bruce-Lockhart, Chairman of the LGA, has written to Adam Crozier, Royal Mail chief executive, expressing "grave concerns" for the council tax payer and the environment.
"I am concerned that the expansion in 'junk mail' will lead to an increase in the amount of paper that is either thrown into landfill or has to be collected in recycling bins," he said.
"This comes at a time when councils are trying to minimise waste, increase recycling and are striving to provide value for money to the taxpayer. Every extra tonne of rubbish that goes into landfill costs the taxpayer an extra #100." ..SUPL: