Equal pay legislation needs to be radically changed if women are to get a fair deal quickly, the Commission for Equality and Human Rights has warned.
Female cleaners, dinner ladies and caretakers are making pay claims
Currently, about 50,000 equal pay cases are being brought by underpaid local council workers.
But the commission says this could rise to 150,000 this year, clogging the tribunal system and forcing women to wait years for what is owed to them.
It wants representative actions, where hundreds of cases are heard together.
The commission says such actions could unblock the tribunal system and reduce the number of cases by more than 90%.
Trevor Phillips, chairman of the commission, told BBC Radio 4's Today programme the current system was on the brink of "meltdown".
He said: "Hundreds of thousands of women are being made to wait - some up to five, 10, years before their cases are settled.
"Women have retired - some have died - before their case has been in the system".
Mr Phillips added: "These women deserve justice now, not justice in another decade.
"They are the care workers who look after your mum, the dinner ladies who look after your children. Every single one of us would suffer if they didn't put in the hours."
He said the Equal Pay Act, introduced almost 40 years ago, had "reached its sell-by date".
'Negotiation not litigation'
"It's time for new legislation, fit for this century, to help sort out this age-old problem," he said.
Local Government Employers has been created to work with local authorities and other bodies to resolve pay, pensions and employment contracts.
Its managing director, Jan Parkinson, blamed a delay in resolving pay issues on a culture of no-win-no-fee lawyers and called for "negotiation and not litigation".
Ms Parkinson said councils were working to achieve equal pay but warned there could be knock-on effects on other services.
"While councils spend around £85bn there will be some implications to some services in some councils despite the work that they are doing to mitigate the effects," she said.