NHS Greater Glasgow and Clyde has asked people not to attend A&E unless it is “life threatening”.
In a post online on Monday, the health board said that its emergency departments are “extremely busy”.
It comes after NHS Lanarkshire announced that it has introduced further visiting restrictions amidst a rise in Covid case numbers.
The health board on Monday said it had decided to take the “difficult decision” to move back to one dedicated visitor per day.
They explained this is able to change day-to-day, but that it must be the same visitor attending the daily 45-minute visiting slots.
The board said that the move would allow it to manage the environment and to maintain physical distancing within multi-occupancy rooms within inpatient areas, as well as across communal areas.
Essential visiting will continue to be supported with staff taking a “compassionate person-centred approach” for each individual patient, the board indicated.
Trudi Marshall, nurse director, said that the priority is to protect patients and staff “as much as is possible”.
“We understand that patients in hospital are having a challenging time and want to have their family and friends around them for support,” she said.
“Unfortunately, we have seen a rise in the number of Covid patients in our hospitals, and it is our priority to protect our patients and staff as much as is possible.
“This is why we have made the difficult decision to have one dedicated visitor each day. The named person will be able to have close contact with their loved one, such as holding hands.
“This will provide those patients in hospital with the vital support they need from family, carers or friends.
“Visiting will continue to be by appointment only and visitors should contact the ward to arrange a time to visit.
“However, we will review this regularly and as soon as it is safe to do so, we will expand visiting again by prioritising access for those closest to the patient and removing the very limiting time restrictions currently in place.
“Anyone with questions about visiting arrangements should speak to the nurse in charge of the ward.”
Ms Marshall also said the board strongly encourages visitors to carry out a lateral flow test.
She said: “While visitors can have close contact with their loved one, they are reminded to adhere to physical distancing in communal areas of the hospital, wear face coverings and frequently wash their hands when entering and leaving clinical areas.
“We would also strongly encourage all visitors to carry out a lateral flow test prior to visiting their loved one.”
She added: “We hope everyone will understand that this decision has been made in the best interests of patients, other visitors and our staff.”