Birmingham City Council spent £35 million on sick pay for staff last year.
And new figures have revealed employees in some departments are taking more than double the national average of days off ill.
The authority spent £34,856,713 on sick pay between January and December last year, according to figures obtained under the Freedom of Information Act.
The council did not reveal the bill for paying agency staff to cover absences, meaning the total cost will be even higher.
Last year, council staff took an average of 9.5 days off sick each – three days higher than the national average.
But between council departments the figures vary wildly.
Staff in the Adults and Communities department are in line to take an average of 16.9 days off sick, over a 12-month period to April.
Employees in the Children, Young People and Families department (not including school staff) and the Homes and Neighbourhoods department are predicted to take 11.3 and 11.8 days off respectively. But members of the Corporate Resources department will only take an average of 6.9 days off ill.
The nationwide average is 6.5 sick days per employee each year, according to CBI figures.
Average absence levels are over a third higher in the public sector, with 8.1 sick days per employee compared to a private sector average of 5.9 days.
At the council, the biggest cause of absence by far was anxiety, stress and depression, which accounted for 23 per cent of days lost due to sickness from April to December last year.
Matthew Elliott, chief executive of the TaxPayers’ Alliance said: “There’s absolutely no reason for the number of days lost to illness at Birmingham City Council to be any higher than private sector averages.
“The gulf in sickness rates between different departments at the council is revealing, a culture change towards days off is clearly needed in some parts of the authority.
“If bosses at city hall reduce the number of days lost to sickies then they could save taxpayers’ a chunk of change without reducing front line services.”
But a Birmingham City Council spokesperson said: “We are determined to reduce levels of staff sickness and the figures are falling on an annual basis.
“Some areas of the council’s work, such as that carried out by the Adults and Communities directorate, involves working with vulnerable service users whose needs, and the potential of passing illness onto these service users, need to be taken into account.
“This is one of the reasons why the figures for those services are above the council-wide average.
“However, plans and strategies are in place and on-going efforts are being made to reduce the levels of sickness in all areas, particularly those that are above average.”
The council spokesman said sick pay will account for less than three per cent of their total employee spend this year.
The Tory-Lib Dem council is ploughing ahead with £62 million cuts to its £3.5 billion budget, while maintaining a council tax freeze for the second year running.
More than 1,100 jobs may go as part of the cuts, but the council said it hopes most people will be redeployed.