Residents have raised concerns after it was announced Calow Post Office is to move to Chesterfield Royal Hospital.
The service will relocate from its current home on Top Road to shop@theRoyal – the hospital’s retail store.
Suzanne Richardson, Post Office regional manager, said: "We are confident this vibrant new-style Post Office at the heart of the community will meet customer needs.
"This modernisation is part of a major investment programme, the largest in the history of the Post Office and will secure services for the future."
However, scores of people slammed the move on the Derbyshire Times' Facebook page - with many raising concerns about parking at the already busy hospital site.
A Post Office spokesman said: "There are several car parks including designated disabled parking facilities at Chesterfield Royal Hospital. There is free parking for up to 30 minutes - but charges then apply upon leaving.
"There is a frequent bus service available between the current branch and the new premises. The nearest bus stop is within 50 metres of the hospital main entrance.
"Access will be level with wide automatic doors at the main entrance. Internally, there will be a hearing loop and space for a wheelchair.
"The majority of Post Office products and services will still be available at the new premises, which are 910 metres away from the current branch..
"The opening hours, which will increase by an extra 37 hours a week, will ensure that the branch is more convenient as people will now have more choice of when to visit. The branch will open earlier and close later every day."
The Post Office at shop@theRoyal will be open seven days a week, 7am to 8pm Monday to Friday and 9am to 6pm on Saturday and Sunday.
The date for the relocation has yet to be confirmed.