Sickness absences cost Caerphilly County Borough Council almost £1 million a month, according to figures released under the Freedom of Information Act.
On average, nearly 12 and a half working days were lost per council employee to sickness during the 2017/18 financial year.
The council revealed the figures after a Freedom of Information request from the Plaid Cymru group.
However, the council refused to provide figures on the cost of sickness for the 2017/18 financial year, citing the costs of compiling the information would exceed the £450 limit for local government, as set out under Section 12 of the Freedom of Information Act 2000.
But the council did provide information for the month of January 2018, where the cost of sickness totalled £988,103.
Cllr Colin Mann, leader of the council’s Plaid Cymru group, said: “I’m disappointed that in 2019 the council’s information system is not easily and quickly able to draw out the annual cost of sickness across the authority. This clearly needs to be looked at because it is important that all councillors are aware of the costs so they can ensure the issue is tackled.
“It concerns me that given the costs of sickness involved no report has been prepared for council over the past five years.”
“Given the information provided there is clearly a need for a full report on sickness levels, costs and what is being done to reduce the levels of absences. I will be asking for a report.”
A spokesman for Caerphilly County Borough Council said: “There continues to be a concerted effort at all levels across the organisation to tackle sickness absence and we are now seeing positive outcomes.
“It is important to note that the council is the largest employer in the area with over 8,500 employees working in a diverse range of services.
“Our priority is to ensure that our employees have appropriate support in place to remain well in the workplace in order to provide key services to our communities.”