Early Conciliation is a new service set to be introduced from April 2014.
It will mean that anyone who wants to lodge an employment tribunal claim will have to first notify ACAS, which will then have up to a month to attempt to resolve the dispute.
The Department for Business, Innovation and Skills asked ACAS to provide Early Conciliation following the success of a similar voluntary ACAS service called Pre-Claim Conciliation (PCC).
In 2011/12 the number of PCC cases that ACAS dealt with which did not go on to become employment tribunal claims increased to 78% from 74% in the previous year.
Independent research conducted by ACAS in December 2012, looking into PCC among employers and employees, confirmed its success. It found that when staff, management time and legal costs are factored in, employers save on average £2,700 compared with resolving a dispute once an employment tribunal claim has been made.
ACAS chair Ed Sweeney (pictured) said: "Pro-active conciliation that is promptly and appropriately provided is critical to the success of Early Conciliation.
"That's why it is important that the expertise of our conciliators is recognised when setting the framework for the service. It is their careful judgement and skillful intervention that will lead to the early resolution of more disputes.
"The introduction of the new service means significant changes for our experienced conciliators and the systems and processes that support them. We are preparing now to ensure that we are ready to provide a quality Early Conciliation service from April 2014."