People with non-life-threatening conditions are to be asked to make an appointment ahead of attending Wales's biggest accident and emergency unit.
Cardiff and Vale University Health Board is introducing a "phone first" triage system for its Emergency Unit at the University Hospital of Wales.
Patients requiring urgent care will be assessed and signposted to the "most appropriate medical help", the health board said.
Those suffering life-threatening emergencies such as symptoms of a stroke, loss of breathing or a suspected heart attack should still call 999.
The health board said that returning to how patients accessed the Emergency Unit before the coronavirus pandemic was not "deemed safe for our patients or staff".
Emergency Unit consultant Dr Katja Empson said: "By introducing this system, we believe it will help keep our patients and staff safe as it helps reduce overcrowding in the waiting room, allows us to socially distance, and patients can wait in the comfort of their own homes for their scheduled time slot.
"We aim to go live with this system at the end of July but will keep our staff, patients and the public informed nearer the time.
"It's important to emphasise that this will not replace 999 calls; if you have an emergency that is life-threatening such as symptoms of a stroke, loss of breathing or a suspected heart attack then you must still call 999.
"This process will not change."
A similar system is in operation in Denmark, where all but the most ill patients must ring ahead and make an appointment at an A&E unit.
Finance Minister Rebecca Evans told a press conference in Cardiff that First Minister Mark Drakeford is "looking carefully" at the health board's plans.
She urged people to seek medical help where required and said the NHS is "open for patients".
"I know that the First Minister is looking really carefully at what is happening in Cardiff and Vale and assessing how it will work for patients," Ms Evans said.
"What we've said throughout is that the NHS is absolutely still there for people."
Ms Evans said people should not feel "worried or concerned" about phoning for an ambulance or approaching A&E if they require urgent medical attention.
"I wouldn't want anybody to be under any impression that A&E was not the place that they should go if they need to, or that it wouldn't be a safe place for them to go," she added.
