Martin Allen, councillor for Upton and Ripple and Dame Harriett Baldwin, MP for West Worcestershire have both called on Royal Mail to address post delay issues, reported in both Upton and Kempsey.
Dame Harriett has written to the chief executive of Royal Mail about the issue.
Royal Mail has confirmed it is aware of the concerns, and will write directly to Dame Harriett to address them.
It added that the vast majority of mail is still being delivered on time.
Dame Harriett called for an urgent review of the county post delivery service, after receiving a series of reports about missing mail.
Constituents reported to her that they regularly do not see postal deliveries for many days followed by a single bulk of mail, sometimes just once a week or worse.
She said: “In the last few weeks, I have seen a serious increase in the number of people complaining to me about postal deliveries with people reporting that they have had bulk deliveries of post once a week.
“The Royal Mail is coming into its busiest period, and traditionally temporary workers are taken on to deal with the increase in workload, but this seems to me like a problem that has been building over a couple of months.
“My biggest concern is that people may be missing urgent hospital appointments or test results, which are often still sent out through the post. I’ve heard reports of events being cancelled because people cannot rely on a first-class mail delivery service.
“I have asked the chief executive to carry out an urgent review of the postal system which covers my constituency and identify any issues that may be delaying the delivery of mail.”
The Royal Mail was bought by new owners in 2024, but the sale came with a pledge to maintain the obligations to deliver first class mail six days a week.
She added: “This is the time of year when we traditionally take time to thank our local postie and I want to be reassured that any change in ownership hasn’t had an effect on the ability of them to do their jobs well.”
Cllr Martin Allen said: “It has been happening not just in Upton but also in Kempsey.
“Residents are concerned about missing hospital appointments, one resident has been very worried about a financial matter.
“If you don’t get the paperwork in time, that has to come in the post, it can have a significant effect on that person.
“I think the Royal Mail need to fess up and let the residents of Upton and Kempsey know what is happening, so they can plan accordingly.”
A Royal Mail spokesperson said: “We’re aware of the concerns raised and want to reassure the MP and residents that our teams continue to work hard to deliver a reliable service in Upton-upon-Severn, Malvern and the surrounding areas.
“The vast majority of mail is being delivered on time, and we remain committed to delivering six days a week across the UK.
“We will write directly to the MP to address her concerns in full.”