The conciliation service's 2010/11 annual report shows it dealt with 1,054 collective disputes over the period, up 15% from 2009/10.
Pay continued to be the top issue followed by redundancy. Ninety-one per cent of cases, including high profile disputes such as British Airports Authority (BAA), the BBC and London Underground, were either resolved or the parties were moved towards a resolution. British Airways also went on to agree a settlement in June, which incorporates further Acas help.
The figures reveal that the North West of England saw the most cases with 228, closely followed by Scotland with 220. The South West of England had the lowest incidence with 26 cases.
Acas dealt with almost 18,000 disputes between individuals and their employers in 2010/11 through their pre-claim conciliation (PCC) service. This aims to resolve workplace issues before they escalate into costly and stressful tribunal claims and dealt with 80% more cases than the previous year. The proportion of cases where no claim was then made to an employment tribunal rose from 70% to 74% - meaning 13,158 cases were prevented.
The number of claims Acas received for conciliation via employment tribunals fell with just under 75,000 cases, a drop of 15%. Multiple claims - where more than one employee has exactly the same issue - such as equal pay claims, however, remained high. Unfair dismissal continues to be the most common reason for individual conciliation cases.
Ed Sweeney (pictured), Acas chairman, said: "We've had another busy year with increased use of our services. There have been a number of high profile collective disputes and it's encouraging to see employers and trade unions willing to get round the negotiating table to reach agreement.
"The success of our pre-claim conciliation service was highlighted by the Government's proposal to expand it in their Resolving workplace disputes consultation. We know that tackling issues in the workplace as early as possible can save time, money and stress for all involved.
"Our main priority for this year will be to continue supporting economic growth by helping organisations manage their people well, prevent disputes and resolve them where they do occur."
As employers and employees continued to look for expert advice on employment legislation and good practice in the workplace the annual report revealed that the Acas helpline answered almost one million calls on changes to employment legislation such as the removal of the Default Retirement Age as well as workplace rights issues like holiday entitlement.
The Acas website attracted more than four million visits - 400,000 more than in 2009/10.
Equality Act guidance was the most popular with 270,000 page views and Acas trained more than 35,000 employers and employees in good employment practices, a rise of 16% from the previous year.