According to research by commercial law firm EMW Picton Howell, the not-for-profit sector also faces a disproportionately high percentage of employment claims, with 7% of cases before the Employment Appeals Tribunal (EAT) involving charities although they employ 3% of the workforce.
The private sector employs three-quarters of the UK workforce and is involved in 56% of employment cases.
Jon Taylor, head of employment at EMW Picton Howell, said: "Many employment cases arising from the raft of redundancies in the recession have yet to reach the appeal stage at the EAT. When we look at these stats again this time next year the proportion of employment appeals against private-sector companies may have risen substantially.
"Unions play a very important role in the public-sector employment landscape. Strong representation and financial support from the unions to help employees bring their case to the court is the reason why the public sector is involved in such a high proportion of employment claims.
Significant alterations to working practices in the form of hiring freezes, below-inflation salary settlements and tougher productivity management will inevitably cause resentment among workers. If handled improperly, they could spark many grievance claims.
"Reducing benefits, such as pension entitlement and sickness pay, is also a sensitive topic that can easily erupt into legal action."