The plan, outlined by Gordon Brown in his speech to last week's Labour Party conference, is intended to give more than one in three two-year-olds access to free childcare for ten hours a week by the end of the next Parliament.
The Government said that the aim was to redirect money to where it is needed most, to help disadvantaged children access high quality childcare.
However, parents who use vouchers are due to lose out on around £1,000 a year.
This will not affect those currently using vouchers to pay for nursery care, as the move does not come into effect until April 2015. Tax relief will still be available for those parents who use workplace nurseries.
The four leading childcare voucher companies - Accor Services UK, Computershare Voucher Services (formerly Busy Bees Childcare Vouchers), Grass Roots and Sodexho Pass - said that childcare vouchers were an extremely popular employee benefit that must be protected, and that the Government had also previously acknowledged their popularity with employers and parents.
Simon Moore, managing director of Computershare Voucher Services, told Nursery World, 'Hard-pressed working people will lose the benefit.'
He added that while Gordon Brown's speech referred to a commitment to frontline delivery of the NHS, 'a large proportion of NHS and PCT staff are on our books. A nurse came up to me at the conference and said that she wouldn't have been able to go back to work without these vouchers.'