Unite general secretary Sharon Graham has urged ministers to ensure a new hospitality employment initiative protects both young recruits and existing workers.
The government and UKHospitality announced a partnership on 15 October targeting 100,000 paid jobs over three years for 18- to 24-year-olds outside education, employment or training.
Responding the following day, Graham said young people needed quality apprenticeships and properly paid employment, rather than opportunities that exposed them to exploitation.
Unite wants safeguards against employers replacing existing workers or using recruitment support to suppress pay and conditions.
The union also called for greater investment in apprenticeships and lifelong learning.
Work and Pensions Secretary Pat McFadden said the partnership would help unemployed young people take their first steps into work and build careers.
Unite's intervention focuses on the quality and security of those opportunities, alongside the programme's recruitment target.
