Cambridge Council Staff Sick Leave
Cambridge City Council's 1,200 employees have each taken an average of 9.63 sick days in this financial year.
That number is expected to rise to 11 days each by the end of March, and means as a whole the authority will lose the equivalent of 36 years in sick days by then.
The figure is almost double that of private sector workers.
Opposition councillors claim high levels of sickness at the authority are damaging services like planning and rubbish collection.
Labour group leader Lewis Herbert said: "Now the sickness level has reached a staggering level and is damaging services for residents.
The council must make it a top priority to understand and deal with the causes of the problem.
If there are stress and poor management issues these need sorting out urgently ."
Executive councillor Rod Cantrill, a member of the leading Liberal Democrat group, blamed swine flu for high sickness levels, and said: "It is something we are very conscious about.
I'm not happy about it and we will look at ways to reduce these figures.
Swine flu has had an impact this year and lots of our workforce undertake manual tasks, which means they are more susceptible to injuries or illness ."