More than 14,000 working days were lost to mental health problems by council staff in Wakefield in one year.
The figures, which cover the period between October 2017 and September 2018, show that mental health issues were the biggest cause of absence among the authority's workforce.
The number of staff forced off work by long-term illness of all kinds has increased too.
A total of 144 workers had been off for four weeks or longer in September 2018, a rise of 19 from the end of the previous July.
After mental health, back problems, broken bones and planned surgery were the most common reasons for long-term absence.
Viruses, common colds and the flu were the most likely explanation for short-term absence, the figures showed.
Gillian Connolly, Wakefield Council’s corporate director for business change, said: "We take the health and wellbeing of all of our employees seriously.
"With one in four people affected by a mental health issue at some stage of their lives this is the most common reason for sickness absence in UK workplaces.
"We provide active support to staff returning to work and to remain in work who have experienced a mental health issue.
"The council provides training to managers to enable them to give appropriate support to staff regarding their mental health.
"We also work to national guidance and have signed up to Time To Change and Mindful Employer - initiatives to provide advice and support to promote the wellbeing of all staff.”
The issue is included in a report which will go before a group of senior councillors next week.
Number of council staff on long-term sick in September 2018 - 144
Working days lost to mental health problems in one year - 14,031 (12,517 long-term)
Days lost to broken bones, back problems and other skeletal issues - 8,916
Days lost to viruses, colds and flu - 5,292 (989 long-term)
Days to lost to planned surgery and subsequent recovery - 4,667