Norfolk and Waveney's care system, covering three hospitals, the ambulance service, community and social services, has declared a critical incident.
Hospital trusts elsewhere have also declared critical incidents amid staff shortages and pressures from Covid-19.
University Hospitals of Morecambe Bay NHS Trust, Blackpool Teaching Hospitals and Great Western Hospitals in Wiltshire have all raised the alarm.
Derriford hospital in Plymouth has problems offloading ambulances, and has recorded nearly 500 staff absences.
Critical incidents are declared when health bosses are concerned they cannot provide priority services.
This includes treatment for cancer or heart disease patients.
(5, Jan 2022)