By declaring the critical incident, it will allow the health and care body to "take additional steps to maintain safe services for our patients and help us cope with the growing pressures," Cath Byford, chief nurse at NHS Norfolk and Waveney Clinical Commissioning Group (CCG) said.

It comes as NHS services across the country have been struggling with demand amid rising coronavirus cases and patients being admitted to hospital.

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"We are seeing large numbers of very unwell people requiring 999 ambulance services and urgent hospital care," Ms Byford said.

"There are also ongoing challenges in discharging patients who are well enough to leave hospital, and we are seeing an increase in staff sickness - all of which leads to longer waits than we would like for patients to be seen and admitted."

In Norfolk and Waveney the three main hospitals are Norfolk and Norwich University Hospital NHS Foundation Trust, James Paget University Hospitals NHS Foundation Trust and the Queen Elizabeth Hospital King's Lynn NHS Foundation Trust.

Absences having 'massive impact' on NHS

Sky News earlier reported around 12 hospital trusts have declared critical incidents.

These include Morecambe Bay NHS Trust, Blackpool Teaching Hospitals NHS, University Hospitals Plymouth NHS Trust, United Lincolnshire Hospitals NHS Trust, Gloucestershire Hospitals NHS Foundation Trust and Great Western Hospitals NHS Foundation Trust.

Chris Hopson, chief executive of NHS Providers, which represents health trusts, told Sky News that absences are having a "massive impact" on the NHS, which is "really struggling in some places".

In a letter to Health Secretary Sajid Javid, the Royal College of Nursing (RCN) said the NHS can "ill afford" the current level of absences as it called for a "more cautious approach" to COVID restrictions in England "without further delay".

Figures released on Tuesday showed the UK reported more than 200,000 new COVID cases for the first time.

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Non-urgent care paused

A sharp rise in coronavirus cases in Greater Manchester prompted 17 hospitals to pause some non-urgent surgery and appointments.

The move is a "temporary measure" and will not affect cancer and urgent care - including cardiac surgery, vascular surgery, and transplantation, the Greater Manchester Health and Social Care Partnership said.

About 15% of staff in the region are off ill with the virus or isolating, while one in five people in some hospitals have COVID-19.