Staff working at Lincolnshire hospitals took four times more sick days than the national average last year.
Unison said the new figures highlighted how NHS staff are suffering intense pressure from workloads and claimed that they are at “breaking point.”
Across all three trusts in the county, the staff took off 169,656 sick days, which comes to an average of 17.1 days per employee.
Office for National Statistics data showed that employees took an average of 4.1 sick days in 2017.
Elliot Dean, the Unison regional organiser, said: “A decade of cuts is taking a terrible toll on all employees, both on their mental and physical health.
“NHS staff across the county have reached a breaking point.
“Fair funding for health and social care services across Lincolnshire is needed urgently.”
Martin Rayson, director of HR at ULHT, said: “Staff health and wellbeing is a high priority for the Trust as we are well aware that an engaged, supported and healthy workforce results in better outcomes for patients.
“We have a focus on continuously reducing levels of staff sickness and have a range of services and events in place to support staff. Our aim is to keep people healthy and get them back to work as quickly as possible if they are sick.
“Recognising that the two largest causes of sickness are muscle and joint issues, and stress, all staff at ULHT can self-refer to our physiotherapy service and we have an occupational health department who carry out work-based assessments as a preventative measure.
“Additionally, we have a counselling service which staff members can self-refer to if they feel they need support with stress and anxiety and we also run workshops on resilience for managers and staff, mental health well-being and mindfulness.”