An auditor’s report into redundancy payments made to council staff had uncovered almost £33,000 in overpayments.

Now Wiltshire Council is writing to the staff, one of whom received more than £15,000 too much, to get the money back.

A second report has also highlighted concerns about the way Kennet District Council paid one-off bonuses to staff for good performance.

The reports, by top auditor KPMG, were commissioned by Wiltshire Council chief executive Keith Robinson into the way redundancy payments were handled by the former Wiltshire Council and the four district councils – North Wiltshire, Kennet, West Wiltshire and Salisbury – in the lead-up to the merger into one authority in April.

More than £5.2 million was paid out to around 60 staff, and the news that councillors overseeing the merger had agreed redundancy packages four times the statutory limit caused outage among council taxpayers.

Mr Robinson said the poor publicity was not the reason for the audit. “I wanted to be sure they had been done correctly,” he said.

The auditors found eight members of staff had been overpaid and six underpaid. The overpayments ranged from £81 to £15,025 for one former officer.

“It was purely down to arithmetic,” said Mr Robinson. “We made a mistake and we have written to apologise.”

Council solicitor Ian Gibbons said the letters would be polite but would be followed by legal action if the money is not repaid.

The second report centred on bonuses, or honouraria, payments made to staff at Kennet District Council during the run-up to the merger.

Mr Robinson said the payments, totalling £80,000, were made to staff as an incentive to stop them leaving before the council was merged.

The report highlighted poor audit trails so it was unclear how decisions were made. He added: “We have amended our own policies on this.”