The Welsh Ambulance Service says it is "very concerned at the handover delays that have been experienced recently".
It is "concerned that pressure across all hospitals in Wales has a direct impact on the ambulance response that is able to be provided to patients who call 999 for our help."
"Ambulance crews continue to provide clinical care for patients as they wait to be admitted into hospital and we provide ambulance clinicians, where possible, to care for patients in emergency departments to support the nursing and medical staff in hospitals."
More top news
Well Ex-hurricane Gonzalo certainly made for some heavy weather today. But the winds are already easing.
Club members are being reminded of an official warning scheme, with repeat offenders being asked to leave.
The charity warns it expects a rise in abandonments as Christmas approaches.