The booklet, produced in partnership with the Centre for Effective Dispute Resolution, advises charities to tackle unrest at an early stage in order to stop costs spiralling out of control.
According to the Centre, a dispute such as a discrimination case can cost up to £75,000 if costs such as legal fees, awards and the consequences of negative publicity are taken into account.
CEDR's 38-page guide to mediation, entitled You're not listening to me, is designed to help charities and voluntary organisations of all sizes deal with disputes before they escalate. It is targeted at directors, managers and human resource staff.
Two national charities have recently faced the threat of strike action.
Staff at Child Poverty Action Group held a successful one-day strike over new contracts last month, and RSPCA employees narrowly rejected industrial action in a dispute over job losses.
"Mediation opens up effective lines of communication between people which may avert more disruptive and damaging action arising further down the line," said Joanna Wootten, human resources manager at NCVO.
The CEDR is an independent non-profit-making organisation, which also operates a Home Office-funded mediation service for the voluntary sector, called CEDR Solve.
The chief charity commissioner, John Stoker, welcomed the guide, and said that mediation had "helped charities to effectively resolve several difficult and seemingly intractable disputes".
For more information about the CEDR Solve mediation service, call 0800 2798 798.