Kent County Council is facing renewed calls for an investigation into its payroll system after another case of an employee being overpaid by thousands of pounds emerged.

Opposition parties say the latest case, which dates back to 2008, justifies a full inquiry into the issue.

Care worker Sheila Ferris, from Margate, was wrongly overpaid a total of £21,000 in two instalments of £15,000 and £6,000. The money has been recovered.

It follows the disclosure that council leader Paul Carter saw thousands of pounds of his own allowances wrongly paid to a maintenance worker by the same name. The money is still outstanding.

Opposition Liberal Democrat leader Cllr Trudy Dean said: "KCC says that over 99% of employees are paid correctly, but given the size of the workforce, that could mean many are not. I would like to know the extent of this and whether it is happening in other departments.”

She has asked for the matter to be considered by KCC’s backbench scrutiny committee.

A Kent County Council spokesman said: "Obviously these errors should not have happened, and we apologise to the individuals for any distress this caused.

"However, we would point out that all these cases relate to errors that happened more than three years ago. This absolutely doesn’t mean we’re complacent.

"KCC employs more than 12,000 people, and while we work hard to minimise mistakes, it is human nature that sometimes errors will happen – our aim is to put them right as soon as possible. We do ask staff to help us by checking their payslips, and when we are notified of an issue we put it right as soon as we can."