The number of cases taken to employment tribunals slumped by 79% last year following the controversial introduction of fees, new figures have revealed.
Unions said the statistics confirmed their warnings that workers would be discouraged from taking claims for unfair dismissal and other complaints.
Charges of £250 to issue a claim and between £960 and over £1,000 for a hearing came into force last July.
Official figures showed there were 79% fewer cases between October and December last year compared with the same period in 2012.
Maria Ludkin, legal officer of the GMB union, said: "These figures confirm our fears that government changes to time limits and introduction of fees has had a devastating impact on access to justice for working people.
"To suggest a 79% reduction is part of a long term declining trend is frankly laughable. Charging £250 to issue a claim and between £960 and £1,060 for a hearing has priced workers out of tribunals.
"We predicted that this would happen but it fell on deaf ears in a government made up of the multimillionaire elite."
Kiran Daurka, employment lawyer at Slater & Gordon, said: "Whilst this is a depressing statistic, it is not surprising to us. We rightly feared that the introduction of fees would be a substantial hurdle to accessing justice for everyday workers and employees, and our concerns have been borne out.
"The biggest groups of people that are losing out are mothers and disabled workers who are amongst the most discriminated groups in the workplace already.
"The Government sought to justify the fees by stating that they would weed out unreasonable claims, but we can see that the fees have deterred a large number of claims, including genuine claims that should have been commenced in the Tribunal.
"The fees have had a very detrimental impact on wronged workers who are now unable to seek justice."
Justice Minister Shailesh Vara said: "It is in everyone's interest to avoid drawn out disputes which emotionally damage workers and financially damage businesses. That's why we are encouraging quicker, simpler and cheaper alternatives like mediation and arbitration.
"It is not fair for the taxpayer to foot the entire £74 million bill for people to escalate workplace disputes to a tribunal. And it is not unreasonable to expect people who can afford to do so, to make a contribution. As for those who cannot afford to pay, fee waivers are available."