Sick days taken by refuse collectors have cost Newcastle Borough Council more than £150,000 in seven months.
Latest figures show they took 1,275 days off sick between April and the middle of November.
At certain times up to 20% of the workforce have been absent through sickness.
Long-term sickness accounted for 974 of the absences – with £113,559 paid out on agency staff and ‘backfill costs’.
Short-term absence was to blame for an extra 301 days off – at a cost of £41,337.
Head of recycling and fleet services Andrew Bird told the authority’s economy, environment and place scrutiny committee: “Sickness has been particularly challenging. It has had a significant effect on our ability to run a service every day. We need a certain number of employees to run the service.
“We do have a pool of staff to cover sickness and absence but it is not enough to cover 20 per cent of the workforce being off at any one time. Then we have to bring agency staff in.”
The worst month for long-term sickness was September when nine employees took a total of 178 days off sick at a cost to taxpayers of £16,884. The most expensive month for short-term absence was last June when 47 days were lost to absence at a cost of £16,045.
Committee chairman Councillor Gary White said: “No organisation can cope with that level of absenteeism. When you look at the cost it’s over £150,000 just to use agencies, as well as impacting on existing employees who probably have to work harder because the agency staff won’t have the same level of experience.
“Our concerns have been raised with the head of the council and the chief executive about the high level of absence. We have asked for support from human resources to focus on this.”
Committee member Mark Olszewski asked if the nature of the sickness absences was known.
He said: “I think we need to explore the causes of the sickness. Is it work-related injuries or is it stress?”
Mr Bird responded: “It is something we do monitor. Sickness and diarrhoea tend to be short-term illnesses.
“We have had eight or nine on long-term sickness on and off. There are only two of those due to industrial injury; the others were other health-related issues.
“However we still need to examine that because there are preventative measures we can do – training around cleanliness.
"During the summer we provided water because we didn’t want people getting dehydrated and it’s worth us exploring some of those other aids we could help with – and flu jabs may be one.”