The urgent care centre at Purley Hospital will close temporarily next week as part of £11m refurbishment work.
The centre, which provides emergency treatment for non life-threatening injuries, will close from December 3 to 9 to allow the work to continue safely.
The centre will reopen on Monday, December 10, with its usual opening hours but there will be no access to X-ray facilities until March 2013 when the centre will be fully operational again with supporting imaging services.
During this time, people requiring urgent X-rays will be redirected to the Urgent Care Centre at Croydon University Hospital.
From December 10 the Urgent Care service will also no longer be able to receive patients arriving by ambulance, because of limited space in front of the building and congestion due to the heavy vehicle traffic in and out of the site during this phase of construction.
Car parking is also limited and the hospital will only be able to provide a drop-off service for people bringing patients to the UCC.
The hours of the walk-in X-ray service at Croydon University Hospital have been extended to Monday to Friday, 8 am to 7.15pm.
Alternative services for people with urgent but not life threatening conditions can be found at the Minor Injuries Unit (MIU) in Parkway Health Centre, New Addington, the 24-hour Urgent Care Centre (UCC) at Croydon University Hospital and the Edridge Road Community Health Centre.