Government inspectors have found people in Northampton have to wait almost twice as long as the national average to get their council tax and housing benefits.
But Northampton Borough Council was praised as providing a "fair" performance, in a report by the Benefit Fraud Inspectorate (BFI).
At the time of the inspection, in July 2003, the council had more than 3,000 items of work outstanding, adding to processing times.
New housing benefits claims took an average 62 days to clear compared with the national target of 36 days.
The report did however conclude that the council had made significant improvements in the areas of counter-fraud and working with landlords since the BFI's last inspection in April 2000.
A BFI report said: "The council had developed a prosecution policy, which supported prosecutions against benefit fraudsters.
"This demonstrates that the council is serious about tackling benefit fraud."