In the 10 years since the fight over inequalities in pay between men and women working for the council came to light, just five percent of claims have been dealt with.

The battle for equal pay began in 2007 when councils across the country were confronted by claims that some female council workers were earning less than male colleagues for doing a similar job.

A total of 605 out of 629 (95 per cent) equal pay claims at NAC remain outstanding - the highest percentage in Scotland, with the national average of around one-third.

NAC has around £3m set aside to deal with existing claims, plus a further £1million for any future cases arising.

The SNP have hit out after the figures were revealed in an Audit Scotland report.

The dispute has been ongoing since 2007, during which time both the SNP and Labour administrations have failed to speed up the process.

North Ayrshire Council claims that the delay was due to the result of a tribunal case involving Glasgow City Council’s job evaluation scheme, which campaigners argue would continue to leave female workers worse off than their male colleagues.

It also indicated that annual reviews are in place to address equal pay issues.

At a recent Audit and Scrutiny Committee meeting SNP Deputy Leader Alan Hill asked for a full report on the current situation.

He said: “This is a concerning situation for the 605 individuals involved and their families. We need to find a way to resolve these cases as soon as possible. We must also put measures in place to ensure that such an injustice can never be repeated.

“For that reason we have asked for an update on a variety of factors, including the progress on currently outstanding equal pay claims and the Council’s approach to proactively carrying out equality work around the gender pay gap.

“We have also called for an action plan on the council’s equal pay policy. We hope that these matters can now be progressed swiftly.”

It is understood that the council aims to deal with the outstanding cases quickly following the Glasgow tribunal outcome.

A North Ayrshire Council spokesperson said: “We delayed settling the majority of our equal pay claims until the Glasgow City Council Employment Tribunal case and appeal outcome was known – a decision which could potentially impact on all local authority equal pay settlements in Scotland.”

“Now that we are aware of the outcome, we can ensure any outstanding claims are settled to the satisfaction of claimants, the trade unions and the council.”