Surrey County Council has apologised to employees after an error with its £30m payroll system saw staff paid the wrong wages.
Problems with its Enterprise Resource Planning system, which was introduced last June, have meant some employees including firefighters and teachers have been underpaid.
Surrey County Council Trade Unions group, which brings together unions including Unison, the National Education Union, NASUWT and the Fire Brigades Union, told the BBC that it has been helping staff with wage errors since the payroll system was introduced, and a fix is not expected to be rolled out until this summer.
A group spokesman said: “These errors include large overpayments and underpayments, which have had dire reverberations for the staff in question. This includes employees being unable to make payments on their mortgage, rent, cars and utilities.”
The council has made several emergency payments to employees.
A Surrey County Council spokesperson said: “We have put in place a number of workarounds and extra resources to try to minimise the impact on staff and schools, and a dedicated technical team is working to resolve underlying issues.
“The recovery plan is making good progress, with the number of errors reducing significantly over time including updating leavers’ processes and the school financial reporting system, and a programme of engagement clinics has also been coordinated to provide individual schools [or] settings with focused support.
“We are still working through some of the issues and we are grateful to our staff and schools for both their efforts and patience as we continue to do this. Some level of disruption was expected throughout such a fundamental transition to a new system, but we are sorry for any inconvenience to employees and schools adversely affected.”