More NHS staff are off sick with Covid-19 as next week's heatwave is set to heap extra pressure on the health service.

The UK Health Security Agency has increased its heat health warning from level three to level four for Monday and Tuesday next week – meaning that "illness and death may occur among the fit and healthy, and not just in high-risk groups".

And NHS leaders say services across the area remain very busy and are calling on the public to use services wisely – adding that this will ensure emergency care is available for those who need it most.

East Suffolk and North Essex NHS Foundation Trust (ESNEFT), which runs Colchester and Ipswich hospitals and community services in north-east Essex and east Suffolk, reported 271 of their 11,600 staff were off work due to Covid.

At West Suffolk NHS Foundation Trust 97 members of a 5,100-strong workforce were off because of the virus.

Nick Hulme, ESNEFT chief executive, said: "The heatwave coming at a time when we have been seeing more Covid-19 hospital admissions and an increase in staff infections does, of course, present us with some challenges but we have robust adverse weather and contingency plans in place to make sure we are ready for all eventualities.

“As part of those plans, we are monitoring our ward temperatures closely and have air cooling units out in key clinical areas. Regular fluid and ice lolly rounds are also made to the wards to help our patients stay cool.

“Our services are running as normal and, as always, our teams are working extremely hard to care for all our patients, both with and without Covid-19, safely – not just in our hospitals, but in patients’ homes and in the local community too.

“With the temperatures expected to continue, our advice to all our patients, visitors, and staff is to stay hydrated and if you’re going to be out and about, enjoy the sun safely and look out for each other while it is so warm.”

Peter Smye, medical director at Suffolk Local Medical Committee, and a GP in Bury St Edmunds, said around 10% of the staff at his surgery were currently off sick.

He said: "Heat does put a little bit more pressure on the system, but the reality is, the NHS at the moment is under so much pressure anyway a little bit extra is only going to make it worse."