Newark Hospital is restricting visitors after a spike in coronavirus cases in the area.
Public Health bosses said they have "serious concerns" after 34 confirmed cases over the last seven days.
The figures mean Newark and Sherwood district has the 15th highest rate for England and health bosses are now looking at how to "reverse this trend".
Due to the increase in Covid-19 cases in community, Sherwood Forest Hospitals has made the decision to restrict visiting at Newark Hospital to help keep patients and staff safe.
From August 12, until further notice, no visiting will be permitted at Newark Hospital unless the patient is receiving end of life care, the patient requires a carer or the patient has significant cognitive impairment or a diagnosis such as dementia or autism.
Visitors will also not be banned if the the patient is a child, with one parent being permitted.
Chief Nurse Julie Hogg from the hospital said: "We have seen a significant rise in the infection rate of Covid-19 in the community and so we are taking steps to help protect our patients and staff.
"We know it is not easy for our patients and their families to be in hospital without visiting and we will do all we can to keep you in touch with each other.
"We hope that you understand that we need to take these precautions for now to ensure the safety of everyone at the hospital."
The visiting restrictions apply to both inpatients and outpatients, but they are still encouraging people to come to the hospital alone if they have an appointment.
A new testing site was launched in Newark on August 10, following a spike in cases linked with the Bakkavor Desserts factory in Jessop Way.
Residents, as well as the local MP for the area, Robert Jenrick, have backed the decision to add a testing site for those in the community in the hope it will curb the rise in cases.
