Workplace disputes could be resolved earlier with greater understanding from union officials of how the collective conciliation process works, according to Acas.
The call came after an Acas survey of more than 1,000 trade union officials showed that 49% indicated that the lack or non-use of Acas was due to the incorrect belief that they could only use the conciliation service if the parties were at an impasse.
Nearly one in six (58%) respondents wrongly thought that conciliation resulted in a solution being chosen for the parties by Acas, while a quarter did not know that Acas is independent of government.
In 2009/10, Acas dealt with more than 900 collective disputes. The vast majority (94%) of cases, including high profile disputes such as Royal Mail and Milford Haven Port Authority, were either resolved or the parties were moved towards a resolution.
Ed Sweeney, Acas chair, said: "A lack of understanding on how we help parties in dispute could be holding some union officials back in using Acas earlier in a dispute, before parties have reached a deadlock and positions become entrenched.
"As we enter potentially difficult times in both the public and private sector, a neutral, impartial third party is a valuable tool to use at the right time. Acas collective conciliation allows the parties to stay in control and helps them to keep communicating and think through what the options for potential resolution might be."