More than 200,000 care workers are receiving illegal wages below the minimum wage, a union has claimed.
Unison said councils across England and Wales are not ensuring homecare companies pay staff for travel time leading to hourly rates below the statutory £6.70.
Research conducted by the union, published ahead of a debate in parliament, showed three out of four local authorities in England, and more in Wales, do not stipulate in their contracts that employees should be paid for travel time.
"More councils might now be insisting that homecare contracts ensure payment for travel time, but there's still too many that don't," Unison general secretary Dave Prentis said.
"This shows just how little local authorities value care staff who do such a vital job looking after the elderly and disabled."